More stuff

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2026-04-08 14:42:50 -03:00
parent a588dcb40a
commit 704b6fec60
11 changed files with 1445 additions and 0 deletions

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/* Problem URL: https://codeforces.com/problemset/problem/2038/C */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n;
cin >> n;
map<ll, int> c;
rep(i, n) {
ll x;
cin >> x;
c[x]++;
}
vi a;
repv(i, c) {
i.second -= (i.second & 1);
while (i.second--) {
a.push_back(i.first);
}
}
if (a.size() < 8) {
cout << "NO\n";
return;
}
cout << "YES\n";
cout << a[0] << ' ' << a[2] << ' ' << a[1] << ' ' << a[a.size() - 1] << ' ' << a[a.size() - 3] << ' ' << a[2] << ' ' << a[a.size() - 3] << ' ' << a[a.size() - 1] << '\n';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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/* Problem URL: https://codeforces.com/problemset/problem/2038/G */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n;
cin >> n;
auto ask = [&](string c) {
cout << "1 " << c << endl;
int ans;
cin >> ans;
return ans;
};
auto answer = [&](int i, int c) {
cout << "0 " << i << ' ' << c << endl;
int ans;
cin >> ans;
};
int a1 = ask("1");
int a11 = ask("11");
int a10 = ask("10");
if (a1 != a11 + a10) {
answer(n, 1);
return;
}
answer(n, 0);
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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/* Problem URL: https://codeforces.com/contest/2217/problem/A */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n, k;
cin >> n >> k;
vi a(n);
cin >> a;
int c = 0;
rep(i, n) {
c += a[i] & 1;
}
if ((c & 1) || (~k & 1) || ((k & 1) && (~n & 1))) {
cout << "YES\n";
return;
}
cout << "NO\n";
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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/* Problem URL: https://codeforces.com/contest/2217/problem/B */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n, k;
cin >> n >> k;
vi a(n);
cin >> a;
int p;
cin >> p;
p--;
int a1 = 0;
for (int i = p - 1; i >= 0; i--) {
a1 += a[i] != a[i + 1];
}
int a2 = 0;
for (int i = p + 1; i < n; i++) {
a2 += a[i] != a[i - 1];
}
cout << max(a1 + (a[0] != a[p]), a2 + (a[n - 1] != a[p])) << '\n';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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/* Problem URL: https://codeforces.com/contest/2217/problem/C */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
ll n, m, a, b;
cin >> n >> m >> a >> b;
if (gcd(n, a) != 1 || gcd(m, b) != 1 || gcd(n, m) > 2) {
cout << "NO\n";
return;
}
cout << "YES\n";
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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/* Problem URL: https://codeforces.com/problemset/problem/1941/F */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n, m, k;
cin >> n >> m >> k;
vl a(n);
vl d(m);
vl f(k);
cin >> a >> d >> f;
map<ll, int, greater<>> c;
rep(i, n - 1) {
c[a[i + 1] - a[i]]++;
}
if (c.begin()->second > 1 || c.begin()->first == 1) {
cout << c.begin()->first << '\n';
return;
}
sortv(d);
sortv(f);
ll lim = c.begin()->first;
int choice = 0;
rep(i, n - 1) {
if (a[i + 1] - a[i] == lim) {
choice = i;
break;
}
}
auto getlesseq = [&](ll mid) {
ll ans = -1;
rep(i, m) {
auto itr = upper_bound(all(f), mid - d[i]) - f.begin();
if (itr == 0) {
continue;
}
rmax(ans, d[i] + f[itr - 1]);
}
return ans;
};
auto getgreatereq = [&](ll mid) {
ll ans = OO;
rep(i, m) {
auto itr = lower_bound(all(f), mid - d[i]) - f.begin();
if (itr == k) {
continue;
}
rmin(ans, d[i] + f[itr]);
}
return ans;
};
ll ch = a[choice];
ll bt = max(ch - a[choice], a[choice + 1] - ch);
auto getans = [&](ll m) {
if (m < a[choice] || m > a[choice + 1]) {
return;
}
ll tbt = max(m - a[choice], a[choice + 1] - m);
if (tbt < bt) {
bt = tbt;
ch = m;
}
};
ll mid = (a[choice] + a[choice + 1]) >> 1;
getans(getlesseq(mid));
getans(getgreatereq(mid));
a.push_back(ch);
sortv(a);
ll ans = 0;
rep(i, n) {
rmax(ans, a[i + 1] - a[i]);
}
cout << ans << '\n';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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/* Problem URL: https://codeforces.com/problemset/problem/1969/C */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n, k;
cin >> n >> k;
vl a(n);
cin >> a;
vvl sparse(20, vl(n));
rep(i, n) {
sparse[0][i] = a[i];
}
nrep(j, 1, 20) {
for (int i = 0; i + (1 << (j - 1)) < n; i++) {
sparse[j][i] = min(sparse[j - 1][i], sparse[j - 1][i + (1 << (j - 1))]);
}
}
auto squery = [&](int l, int r) {
int log = 31 - __builtin_clz(r - l + 1);
return min(sparse[log][l], sparse[log][r - (1 << log) + 1]);
};
vvl memo(n, vl(k + 1, -1));
function<ll(int, int)> dp = [&](int i, int c) {
if (i >= n) {
return 0LL;
}
ll &ans = memo[i][c];
if (ans != -1) {
return ans;
}
ans = OO;
for (int j = 0; j + c <= k && i + j < n; j++) {
rmin(ans, dp(i + j + 1, c + j) + squery(i, i + j) * (j + 1));
}
return ans;
};
cout << dp(0, 0) << '\n';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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/* Problem URL: https://codeforces.com/problemset/problem/1919/C */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n;
cin >> n;
vi a(n);
cin >> a;
int x = oo;
int y = oo;
int ans = 0;
rep(i, n) {
if (x > y) {
swap(x, y);
}
if (a[i] <= x) {
x = a[i];
continue;
}
if (a[i] > y) {
x = a[i];
ans++;
continue;
}
y = a[i];
}
cout << ans << '\n';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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@@ -0,0 +1,200 @@
/* Problem URL: https://codeforces.com/problemset/problem/2034/D */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n;
cin >> n;
vi a(n);
cin >> a;
array<int, 3> c = {0, 0, 0};
set<int> o;
rep(i, n) {
c[a[i]]++;
if (a[i] == 1) {
o.insert(i);
}
}
V<pair<int, int>> ans;
auto printans = [&]() {
cout << ans.size() << '\n';
repv(i, ans) {
cout << i.first << ' ' << i.second << '\n';
}
};
nrep(i, c[0], c[0] + c[1]) {
if (a[i] == 1) {
o.erase(i);
continue;
}
}
int val = -1;
nrep(i, c[0], c[0] + c[1]) {
if (o.empty()) {
break;
}
if (a[i] != 1) {
if (o.size() == 1) {
val = i;
break;
}
swap(a[*o.begin()], a[i]);
ans.emplace_back(*o.begin() + 1, i + 1);
o.erase(o.begin());
}
}
set<int> t;
set<int> z;
rep(i, c[0]) {
if (a[i] > 1) {
t.insert(i);
}
}
nrep(i, c[0] + c[1], n) {
if (a[i] < 1){
z.insert(i);
}
}
int ch = c[0];
if (!o.empty()) {
ch = *o.begin();
} else {
if (t.empty() || z.empty()) {
cout << "0\n";
return;
}
ans.emplace_back(*t.begin() + 1, c[0] + 1);
val = c[0];
ch = *t.begin();
t.erase(t.begin());
}
int now = ch > c[0];
while (!t.empty() || !z.empty()) {
if (now) {
ans.emplace_back(*t.begin() + 1, ch + 1);
ch = *t.begin();
t.erase(t.begin());
now ^= 1;
continue;
}
ans.emplace_back(*z.begin() + 1, ch + 1);
ch = *z.begin();
z.erase(z.begin());
now ^= 1;
}
ans.emplace_back(ch + 1, val + 1);
printans();
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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@@ -0,0 +1,139 @@
/* Problem URL: https://codeforces.com/problemset/problem/1787/C */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;
void pre()
{
}
#define TEST 1
void solve()
{
int n;
ll s;
cin >> n >> s;
vl a(n);
cin >> a;
V<pair<ll, ll>> act(n);
rep(i, n) {
if (a[i] >= s * 2) {
act[i] = {s, a[i] - s};
continue;
}
if (a[i] >= s) {
ll diff = a[i] - s;
act[i] = {diff, a[i] - diff};
continue;
}
act[i] = {0, a[i]};
}
vvl dp(n, vl(2, OO));
dp[1][0] = a[0] * act[1].first;
dp[1][1] = a[0] * act[1].second;
nrep(i, 2, n - 1) {
auto [x, y] = act[i];
auto [xb, yb] = act[i - 1];
dp[i][0] = min(dp[i - 1][0] + (a[i - 1] - xb) * x, dp[i - 1][1] + (a[i - 1] - yb) * x);
dp[i][1] = min(dp[i - 1][0] + (a[i - 1] - xb) * y, dp[i - 1][1] + (a[i - 1] - yb) * y);
}
cout << min(dp[n - 2][0] + (a[n - 2] - act[n - 2].first) * a[n - 1], dp[n - 2][1] + (a[n - 2] - act[n - 2].second) * a[n - 1]) << '\n';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
pre();
int t;
(TEST && cin >> t) || (t = 1);
while (t--) {
solve();
}
}

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@@ -112,6 +112,10 @@ A little collection of interesting problems that I randomly decided to do.
Interesting to think about the transitions and the states, although figuring out Interesting to think about the transitions and the states, although figuring out
it's a dp problem is already a challenge by itself. it's a dp problem is already a challenge by itself.
- [C. Minimizing the Sum](https://codeforces.com/problemset/problem/1969/C)
Simple dp problem, but it's still interesting to think about it.
## Graph ## Graph
@@ -128,6 +132,11 @@ A little collection of interesting problems that I randomly decided to do.
A very simple problem once you finally understand it, interesting to learn about dfs A very simple problem once you finally understand it, interesting to learn about dfs
and all that. and all that.
- [G1. Min-Fund Prison (Easy)](https://codeforces.com/problemset/problem/1970/G1)
A really easy problem, at least it is once you realize that it's just a tree and the
calculation is simple.
## Math ## Math
- [E2. Rudolf and Snowflakes (hard version)](https://codeforces.com/problemset/problem/1846/E2) - [E2. Rudolf and Snowflakes (hard version)](https://codeforces.com/problemset/problem/1846/E2)