Submission #1097288

#	Time	Username	Problem	Language	Result	Execution time	Memory
1097288		nguyen31hoang08minh2003	Fountain (eJOI20_fountain)	C++17	100 / 100	151 ms	13440 KiB

fountain

#include <set>
#include <map>
#include <cmath>
#include <queue>
#include <deque>
#include <stack>
#include <math.h>
#include <bitset>
#include <vector>
#include <string>
#include <cstdio>
#include <cctype>
#include <numeric>
#include <fstream>
#include <sstream>
#include <cstdlib>
#include <iomanip>
#include <cassert>
#include <cstring>
#include <stdio.h>
#include <string.h>
#include <iterator>
#include <iostream>
#include <algorithm>
#include <strings.h>
#include <functional>
#include <unordered_set>
#include <unordered_map>
#define fore(i, a, b) for (int i = (a), i##_last = (b); i < i##_last; ++i)
#define fort(i, a, b) for (int i = (a), i##_last = (b); i <= i##_last; ++i)
#define ford(i, a, b) for (int i = (a), i##_last = (b); i >= i##_last; --i)
#define fi first
#define se second
#define pb push_back
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
using namespace std;
using ll = long long;
using ld = long double;

template<class A, class B> bool maxi(A &a, const B &b) {return (a < b) ? (a = b, true):false;};
template<class A, class B> bool mini(A &a, const B &b) {return (a > b) ? (a = b, true):false;};

typedef unsigned long long ull;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;

constexpr int MAX_N = 1E5 + 5, INF = 0X3F3F3F3F, LOG2_MAX_N = 20;

signed result, h[MAX_N], ancestor[LOG2_MAX_N][MAX_N], floorLog2[MAX_N], sum[MAX_N];
int N, Q, R, V, D[MAX_N], C[MAX_N];
stack<int> s;

int findAncestor(const int j, const int i) {
    if (i > N)
        return i;
    return ancestor[j][i];
}

int findSum(const int x, const int y) {
    return sum[x] - sum[y] + C[y];
}

signed main() {

    #ifdef LOCAL
    freopen("input.INP", "r", stdin);
//    freopen("output.OUT", "w", stdout);
    #endif // LOCAL
    cin.tie(0) -> sync_with_stdio(0);
    cout.tie(0);

    cin >> N >> Q;

    D[N + 1] = INF;

    fort(i, 1, N)
        cin >> D[i] >> C[i];

    s.push(N + 1);

    ford(i, N, 1) {
        for (; !s.empty() && D[s.top()] <= D[i]; s.pop());
        ancestor[0][i] = s.top();
        h[i] = h[ancestor[0][i]] + 1;
        sum[i] = sum[ancestor[0][i]] + C[i];
        s.push(i);
    }

    for (int j = 1; (1 << j) <= N; ++j)
        fort(i, 1, N - (1 << j) + 1)
            ancestor[j][i] = findAncestor(j - 1, findAncestor(j - 1, i));

    fort(i, 2, N)
        floorLog2[i] = floorLog2[i >> 1] + 1;

    fort(_, 1, Q) {
        cin >> R >> V;

        if (V > sum[R]) {
            cout << 0 << '\n';
            continue;
        }

        if (V <= C[R]) {
            cout << R << '\n';
            continue;
        }

        result = R;

        ford(j, floorLog2[h[R]], 0)
            while (result != ancestor[j][result] && findSum(R, ancestor[j][result]) < V)
                result = ancestor[j][result];

        result = ancestor[0][result];

        cout << result << '\n';
    }

    return 0;
}

/*

    Use binary-lifting
        (with prefix sum...)

*/

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