Submission #630920

#	Time	Username	Problem	Language	Result	Execution time	Memory
630920		pragmatist	Fountain (eJOI20_fountain)	C++17	100 / 100	661 ms	31692 KiB

fountain

/*#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("O3")
#pragma GCC target ("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")*/

#include<bits/stdc++.h>

#define sz(v) (int)v.size()
#define ll long long
#define pb push_back
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define nl "\n"

using namespace std;
using pii = pair<int, int>;

const int N = (int)1e5 + 7; // make sure this is right
const int inf = (int)1e9 + 7;
const ll INF = (ll)1e18 + 7;
const ll MOD = (ll)998244353; // make sure this is right

pii dir[] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

int n, q, d[N], c[N], r[N], up[N][21];
ll sum[N][21];

void solve() {
	cin >> n >> q;
	for(int i = 1; i <= n; ++i) cin >> d[i] >> c[i];
	d[n + 1] = inf;
	stack<int> st;
	st.push(n + 1);
	for(int i = n; i >= 1; --i) {
		while(!st.empty()) {
			int x = st.top();
			if(d[x] > d[i]) {
				r[i] = x;
				break;
			}
			st.pop();
		}
		st.push(i);	
	}
	for(int i = n; i >= 1; --i) {
		up[i][0] = r[i];
		sum[i][0] = c[r[i]];
		for(int j = 1; j <= 17; ++j) {
			sum[i][j] = sum[i][j - 1] + sum[up[i][j - 1]][j - 1]; 
			up[i][j] = up[up[i][j - 1]][j - 1];
		}
	}
	while(q--) {
		int i, e;
		cin >> i >> e;
		if(c[i] >= e) {
			cout << i << nl;
			continue;		
		}
		int l = 1, r = n - i + 1, res = 0;
		while(l <= r) {
			int mid = (l + r) >> 1;
			ll cur = c[i];
			int v = i;
			for(int j = 0; j < 18; ++j) {
				if(mid >> j & 1) {
					cur += sum[v][j];
					v = up[v][j];
				}	
			}
			if(cur >= e) {
				res = v;
				r = mid - 1;
			} else
				l = mid + 1;
		}
		cout << res << nl;
	}	
}   

signed main() {	
	ios_base::sync_with_stdio(NULL);
	cin.tie(0);
	cout.tie(0);
	int test = 1;
	//cin >> test;
	while(test--) {
		solve();
	}
	return 0;
}

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