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Add a bunch of other problems.

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Segcolt
2025-09-12 14:50:25 -03:00
parent 88e542c982
commit 489cb2ba51
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141
ITMO Academy: pilot course - Binary Search - Step 4/A. Maximum Average Segment.cpp Normal file
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/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/4/practice/contest/285069/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;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, d;
cin >> n >> d;
vl fds(n);
cin >> fds;
V<long double> pref(n + 1);
int lans = 1;
int rans = 1;
long double low = 0;
long double high = 1e7;
long double eps = 1e-9;
while ((high - low) >= eps) {
long double mid = (low + high) / 2;
rep(i, d - 1) {
pref[i + 1] = pref[i] + fds[i] - mid;
}
int tmpl = 0;
int tmpr = 0;
bool pos = false;
long double minimal = 0;
int ind = 0;
nrep(i, d, n + 1) {
pref[i] = pref[i - 1] + fds[i - 1] - mid;
if (pref[i - d] <= minimal) {
minimal = pref[i - d];
ind = i - d;
}
if (pref[i] - minimal < 0) {
continue;
}
pos = true;
tmpl = ind + 1;
tmpr = i;
break;
}
if (pos) {
lans = tmpl;
rans = tmpr;
low = mid;
continue;
}
high = mid;
}
cout << lans << ' ' << rans << '\n';
}

159
ITMO Academy: pilot course - Binary Search - Step 4/B. Minimum Average Path.cpp Normal file
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/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/4/practice/contest/285069/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;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
V<V<pair<int, int>>> graph(n);
while (m--) {
int a, b, c;
cin >> a >> b >> c;
graph[a - 1].emplace_back(b - 1, c);
}
vi parent(n);
long double low = 0;
long double high = 1e3;
long double act = 0;
long double eps = 1e-9;
vi next(n, -1);
long double inf = 1e18;
while ((high - low) >= eps) {
long double mid = (high + low) / 2;
V<long double> memo(n, -inf);
function<long double(int)> dfs = [&](int i) {
long double &ans = memo[i];
if (ans != -inf) {
return ans;
}
if (i == n - 1) {
ans = 0;
return ans;
}
ans = inf;
for (auto [j, c] : graph[i]) {
// rmin(ans, dfs(j) + c - mid);
long double tmp = dfs(j) + c - mid;
if (tmp <= ans) {
next[i] = j;
ans = tmp;
}
}
return ans;
};
long double tmp = dfs(0);
if (tmp <= 0) {
high = mid;
act = mid;
continue;
}
low = mid;
}
vi ans = {1};
int now = next[0];
while (now != n - 1) {
ans.push_back(now + 1);
now = next[now];
}
ans.push_back(n);
cout << ans.size() - 1 << '\n' << ans;
}

121
ITMO Academy: pilot course - Binary Search - Step 4/C. Pair Selection.cpp Normal file
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/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/4/practice/contest/285069/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;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, k;
cin >> n >> k;
V<pair<ll, ll>> fds(n);
repv(i, fds) {
cin >> i.first >> i.second;
}
V<long double> vec(n);
long double low = 0;
long double high = 1e10;
long double eps = 1e-12;
while ((high - low) >= eps) {
long double mid = (low + high) / 2;
rep(i, n) {
vec[i] = fds[i].first - fds[i].second * mid;
}
sort(all(vec), greater<>());
long double ans = 0;
rep(i, k) {
ans += vec[i];
}
if (ans >= 0) {
low = mid;
continue;
}
high = mid;
}
cout << setprecision(10) << low << '\n';
}