Submission #1260164

#	Time	Username	Problem	Language	Result	Execution time	Memory
1260164		mingga	Fountain (eJOI20_fountain)	C++20	100 / 100	291 ms	18424 KiB

fountain

// Author: caption_mingle
#include "bits/stdc++.h"

using namespace std;

#define ln "\n"
#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define ll long long
const int mod = 1e9 + 7;
const int inf = 2e9;
const int N = 1e5 + 7;
int n, q, d[N], c[N], nxt[N][20], cap[N][20];

signed main() {
	cin.tie(0) -> sync_with_stdio(0);
	#define task ""
	if(fopen(task ".INP", "r")) {
		freopen(task ".INP", "r", stdin);
		freopen(task ".OUT", "w", stdout);
	}
	cin >> n >> q;
	for(int i = 1; i <= n; i++) cin >> d[i] >> c[i];
	vector<int> st;
	st.pb(0);
	d[0] = inf;
	for(int i = n; i > 0; i--) {
		while(d[st.back()] <= d[i]) st.pop_back();
		nxt[i][0] = st.back();
		cap[i][0] = c[st.back()];
		st.pb(i);
	}
	for(int j = 1; j < 20; j++) {
		for(int i = 0; i <= n; i++) {
			int u = nxt[i][j - 1];
			nxt[i][j] = nxt[u][j - 1];
			cap[i][j] = cap[i][j - 1] + cap[u][j - 1];
		}
	}
	for(int i = 1; i <= q; i++) {
		int r, v; cin >> r >> v;
		if(v <= c[r]) {
			cout << r << ln;
			continue;
		}
		v -= c[r];
		for(int j = 19; j >= 0; j--) {
			if(v >= cap[r][j]) {
				v -= cap[r][j];
				r = nxt[r][j];
			}
		}
		if(v) r = nxt[r][0];
		cout << r << ln;
	}
    cerr << "\nTime: " << clock() * 1000 / CLOCKS_PER_SEC;
}

Compilation message (stderr)

fountain.cpp: In function 'int main()':
fountain.cpp:22:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |                 freopen(task ".INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
fountain.cpp:23:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |                 freopen(task ".OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40