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Segcolt
2025-09-12 14:50:25 -03:00
parent 88e542c982
commit 489cb2ba51
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118
ITMO Academy: pilot course - Binary Search - Step 3/A. Get together.cpp Normal file
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/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/3/practice/contest/285083/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;
cin >> n;
V<pair<ll, ll>> fds(n);
repv(i, fds) {
cin >> i.first >> i.second;
}
long double ans = 3e9;
long double low = 0;
long double high = 3e9;
long double eps = 1e-9;
while ((high - low) >= eps) {
long double mid = (low + high) / 2;
long double l = -1e18;
long double r = 1e18;
repv(i, fds) {
rmax(l, i.first - (mid * i.second));
rmin(r, i.first + (mid * i.second));
}
if (l <= r) {
ans = mid;
high = mid;
continue;
}
low = mid;
}
cout << setprecision(9) << ans << '\n';
}

125
ITMO Academy: pilot course - Binary Search - Step 3/B. Splitting an Array.cpp Normal file
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/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/3/practice/contest/285083/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, k;
cin >> n >> k;
vl fds(n);
cin >> fds;
ll ans = 1e15;
ll low = 1;
ll high = 1e15;
while (low <= high) {
ll mid = (low + high) >> 1;
ll count = 0;
ll now = 0;
ll midans = 0;
int i = 0;
for (; i < n && count < k - 1; i++) {
if (now + fds[i] > mid) {
now = 0;
count++;
}
now += fds[i];
rmax(midans, now);
}
for (; i < n; i++) {
now += fds[i];
}
rmax(midans, now);
if (midans <= mid) {
ans = mid;
high = mid - 1;
continue;
}
low = mid + 1;
}
cout << ans << '\n';
}

116
ITMO Academy: pilot course - Binary Search - Step 3/C. Cows in Stalls.cpp Normal file
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/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/3/practice/contest/285083/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;
vl fds(n);
cin >> fds;
ll ans = 0;
ll low = 1;
ll high = 1e9;
while (low <= high) {
ll mid = (low + high) >> 1;
ll now = k - 1;
ll prev = fds[0];
for (int i = 1; i < n && now > 0; i++) {
if ((fds[i] - prev) >= mid) {
prev = fds[i];
now--;
}
}
if (now == 0) {
ans = mid;
low = mid + 1;
continue;
}
high = mid - 1;
}
cout << ans << '\n';
}

163
ITMO Academy: pilot course - Binary Search - Step 3/D. Minimum maximum on the Path.cpp Normal file
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/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/3/practice/contest/285083/problem/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;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, d;
cin >> n >> m >> d;
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);
int ans = -1;
int low = 0;
int high = 1e9;
while (low <= high) {
int mid = ((high - low) >> 1) + low;
vi p(n);
auto bfs = [&]() {
const int inf = INT32_MAX >> 1;
vi dis(n, inf);
queue<int> q;
dis[0] = 0;
q.push(0);
while (!q.empty()) {
int i = q.front();
q.pop();
for (auto [j, c] : graph[i]) {
if (c > mid) {
continue;
}
if (dis[j] > dis[i] + 1) {
dis[j] = dis[i] + 1;
p[j] = i;
q.push(j);
}
}
}
return dis.back();
};
int now = bfs();
if (now <= d) {
ans = mid;
parent = move(p);
high = mid - 1;
continue;
}
low = mid + 1;
}
if (ans == -1) {
cout << "-1\n";
return 0;
}
vi tmp = {n};
int now = parent[n - 1];
while (now != 0) {
tmp.push_back(now + 1);
now = parent[now];
}
tmp.push_back(1);
reverse(all(tmp));
cout << tmp.size() - 1 << '\n' << tmp;
}