Submission #1236844

#	Time	Username	Problem	Language	Result	Execution time	Memory
1236844		Ekber_Ekber	Fountain (eJOI20_fountain)	C++20	30 / 100	408 ms	37660 KiB

fountain

#include <bits/stdc++.h>
#define GOOD_LUCK ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define int long long
#define itn int
#define endl "\n"
#define ff first
#define ss second
#define pb push_back
#define ppb pop_back
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define bs binary_search
#define count1 __builtin_popcount
#define all(v) v.begin(), v.end()
using namespace std;

struct point{
	
};

int ctoi(char x) {
	return (int)x - '0';
}

int sumab(int a, int b) {
	return (a + b) * (b - a + 1) / 2;
}

int gcd(int a, int b) {
	if (b == 0) return a;
	return gcd(b, a%b);
}

int lcm(int a, int b) {
	return a / gcd(a, b) * b;
}

void print(vector <int> &v) {
	for (const int &i : v) cout << i << ' ';
}

constexpr int MAX = 1e+5 + 3, INF = 2e+9, MOD = 16714589, K = 18;

int temp, temp1, temp2, temp3;
vector <int> g;
pair<int, int> up[K+3][MAX];

void _() {
	int n, q;
	cin >> n >> q;
	vector <int> v(n+1), dia(n+1);
	for (int i=1; i <= n; i++) {
		cin >> dia[i] >> v[i];
	}
	v[0] = dia[0] = INF;
	g.assign(n+1, 0);
	
	// build tree
	// O(n * log(n))
	multiset <pair<int, int>> ms;
	ms.insert({dia[0], 0});
	for (int i = n; i > 0; i--) {
		auto it = ms.lb({dia[i]+1, 0});
		g[i] = (*it).ss;
		ms.insert({dia[i], i});
	}
	// correct
	
	// build up
	// O(n + n * log(n))
	for (int i=1; i <= n; i++) {
		up[0][i] = {g[i], v[i]};
	}
	up[0][0] = {0, INF};
	for (int i=1; i <= K; i++) {
		for (int j=1; j <= n; j++) {
			if (up[i-1][j].ff == 0) {
				up[i][j] = {0, INF};
			}
			else {
				if (up[i-1][up[i-1][j].ff].ff == 0) {
					up[i][j] = {0, INF};
				}
				else {
					up[i][j].ff = up[i-1][up[i-1][j].ff].ff;
					up[i][j].ss = up[i-1][j].ss + up[i-1][up[i-1][j].ff].ss;
				}
			}
		}
	}
	// correct

	// queries
	// O(q * log(n))
	while (q--) {
		int x, y;
		cin >> x >> y;
		int l=0, r=n, ans = -1;
        while (l <= r) {
            int mid = (l + r) / 2;
            int a = x, b = y;
            bool c = 1;
            for (int i = K-1; i >= 0; i--) {
                if (mid & (1 << i)) {
                    if (b <= up[i][a].ss) {
                        c = 0;
                        break;
                    }
                    b -= up[i][a].ss;
                    a = up[i][a].ff;
                }
            }
            // cout << b << ' ' << mid << endl;
            if (c) {
                ans = a;
                l = mid + 1;
            }
            else r = mid - 1;
        }
        cout << ans << endl;
	}
}

signed main() {

	GOOD_LUCK

	int tests=1;
//	cin >> tests;
	while (tests--) {
		_();
//    	cout << endl;
	}

	return 0;
}
// Problem X
// by Ekber_Ekber
/*
8 6
3 5
4 3
2 2
1 3
3 8
5 10
4 5
7 30
4 10
1 3
7 35
6 38
5 8
2 50


8 1
3 5
4 3
2 2
1 3
3 8
5 10
4 5
7 30
7 35

*/

• Subtask 1: 0 / 30
• Subtask 2: 30 / 30
• Subtask 3: 0 / 40