Submission #671833

#	Time	Username	Problem	Language	Result	Execution time	Memory
671833		moday_morning	Divide and conquer (IZhO14_divide)	C++17	100 / 100	35 ms	5980 KiB

divide

#include <bits/stdc++.h>
#define int long long
#define fr first
#define sc second
#define pb push_back
using namespace std;
const int INF = 1'000'000'000'000'000'000LL;

void usaco(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

void solve() {
    int n;
    cin >> n;
    int x[n+1], g[n+1], d[n+1];
    d[0] = 0;
    g[0] = 0;
    for (int i = 1; i <= n; i++) {
        cin >> x[i] >> g[i] >> d[i];
        d[i] += d[i-1];
        g[i] += g[i-1];
    }
 
    vector <pair <int, int>> a, b;
    a.pb({-INF, -INF});
    b.pb({-INF, -INF});
    for(int i = 1; i <= n; i++) {
        a.pb({d[i] - x[i], g[i]});
        b.pb({d[i-1] - x[i], - g[i-1]});
    }
    sort(a.begin(), a.end());
    sort(b.begin(), b.end());
    int sb = -INF, res = 0, ans = 0, cnt = 0;
    for (ans = 1; ans <= n; ans++) {
        while (cnt+1 <= n && b[cnt+1].fr <= a[ans].fr) {
            cnt++;
            sb = max(sb, b[cnt].sc);
        }
        res = max(res, a[ans].sc + sb);
    }
    cout << res << "\n";
}

signed main() {
//    usaco("triangles");
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t = 1;
//    cin >> t;
    while (t--) {
        solve();
    }
}

Compilation message (stderr)

divide.cpp: In function 'void usaco(std::string)':
divide.cpp:10:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
divide.cpp:11:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 31 / 31
• Subtask 3: 52 / 52