Submission #704581

#	Time	Username	Problem	Language	Result	Execution time	Memory
704581		thrasherr_1	Fountain (eJOI20_fountain)	C++17	0 / 100	88 ms	48640 KiB

fountain

#include <bits/stdc++.h>
using namespace std ;

#define ff first
#define ss second
#define ll long long
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define ones(x) __builtin_popcount(x)
#define remove(v)  v.erase(unique(all(v)), v.end())
#define rep(i, a, b) for(int i = a; i <= b; i++)
#define per(i, a, b) for(int i = a; i >= b; i--)

#ifdef local
#include "C:\debug.h"
#else
#define dbg(x...) 42
#endif

#define int ll

const int N = 1e5 + 2 ;

vector<vector<int>> dp(N, vector<int>(20 , 0)) ;
int n , q , d[N] , c[N] , up[N][20] , used[N] ;

vector<int> g[N] ;

void dfs(int v , int p) {
    used[v] = 1 ;
    up[v][0] = p ;
    rep(i , 1 , 17) {
        up[v][i] = up[up[v][i - 1]][i - 1] ;
    }
    for(auto& to : g[v]) {
        if(to != p) {
            dfs(to , v) ;
        }
    }
}

void solve(){
    cin >> n >> q ;
    rep(i , 1 , n) {
        cin >> d[i] >> c[i] ;
    }
    stack<pair<int,int>> s ;
    per(i , n , 1){
        while(sz(s) && s.top().first <= d[i]) s.pop() ;
        if(sz(s)) g[s.top().second].pb(i) ;
        s.push({d[i] , i}) ;
    }
    per(i , n , 1) {
        if(!used[i]) {
            int pr = i ;    
            dfs(i , pr) ;
        }
    }
    per(i , n , 1) {
        dp[i][0] = c[i] ;
        int j = 0 ;
        // cout << dp[i][j] << ' ' ;
        int last = i ;
        rep(k , 0 , 17) {
            j++ ;
            if(up[i][k] == last) {
                dp[i][j] = dp[i][j - 1] ;
            }else{
                last = up[i][k] ;
                dp[i][j] = dp[i][j - 1] + c[up[i][k]] ;
            }
            // cout << dp[i][j] << ' ' ;
        }
        // cout << "\n" ;
    }
    rep(i , 1 , q) {
        int ind , k ; cin >> ind >> k ;
        if(dp[ind][18] < k) {
            cout << 0 << "\n" ;
            continue ;
        }
        if(dp[ind][0] >= k) {
            cout << ind << "\n" ;
            continue ;
        }
        // while(k > 0) {
            auto it = lb(all(dp[ind]) , k) ;
            int pos = it - begin(dp[ind]) ;
            if(pos == 0) {
                cout << 0 << "\n" ;
            }else
                cout << up[ind][pos - 1] << "\n" ;
    }
}

signed main () {
    ios::sync_with_stdio(false) ;
    cin.tie(0) ;
    int test = 1 ;
    // cin >> test ; 
    for(int i = 1 ; i <= test ; i++) {
        solve() ;
    }
}

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