Submission #89253

#	Time	Username	Problem	Language	Result	Execution time	Memory
89253		zoomswk	The Big Prize (IOI17_prize)	C++17	97.61 / 100	59 ms	608 KiB

prize

#include "prize.h"
#include <vector>
#include <algorithm>
#include <set>
using namespace std;

int m, res;
bool flag = false;

void solve(int l, int r, int num, int bef){
    if(num == 0) return;
    if(l > r) return;
    int mid = (l+r)/2;
    vector<int> resp = ask(mid);
    if(resp[0]+resp[1] == 0){
        res = mid;
        flag = true;
        return;
    }
    int b = mid;
    while(resp[0]+resp[1] != m && b < r){
        b++;
        resp = ask(b);
        if(resp[0]+resp[1] == 0){
            res = b;
            flag = true;
            return;
        }
    }
    if(resp[0]+resp[1] == m){
        solve(l, mid-1, resp[0]-(b-mid)-bef, bef);
        if(flag) return;
        solve(b+1, r, num-(resp[0]-bef), resp[0]);
        if(flag) return;
    } else{
        solve(l, mid-1, num, bef);
    }
    return;
}

int find_best(int n) {
    if(n <= 5000){
        for(int i=0; i<n; i++){
            vector<int> resp = ask(i);
            if(resp[0]+resp[1] == 0) return i;
        }
    }
    vector<int> resp;
    set<int> s;
    for(int x=0; x<480; x++){
        int i = x*n/500;
        resp = ask(i);
        if(resp[0]+resp[1] == 0) return i;
        s.insert(resp[0]+resp[1]);
        m = max(m, resp[0]+resp[1]);
        if(s.size() == 4) break;
    }
    
    solve(0, n-1, m, 0);
    
    return res;
}

• Subtask 1: 20 / 20
• Subtask 2: 77.61 / 80