Submission #771939

#	Time	Username	Problem	Language	Result	Execution time	Memory
771939		_martynas	The Big Prize (IOI17_prize)	C++11	90 / 100	69 ms	348 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>

using namespace std;

const int jump = 128;

int find_best(int n) {
    mt19937 rng(0);
    int mx_sum = 0;
    for(int k = 0; k < 500; k++) {
        auto v = ask(rng() % n);
        mx_sum = max(mx_sum, v[0]+v[1]);
    }
    for(int i = 0; i < n; i++) {
        auto v = ask(i);
        int sum = v[0]+v[1];
        if(sum == 0) {
            return i;
        }
        if(sum == mx_sum) {
            vector<int> v_p;
            if(i+jump < n) {
                v_p = ask(i+jump);
                if(v_p[0]+v_p[1] == mx_sum && v[0] == v_p[0]) {
                    i += jump;
                    continue;
                }
            }
            int l = i, r = min(i+jump, n-1);
            while(l < r) {
                int m = (l+r+1)/2;
                v_p = ask(m);
                int sum_p = v_p[0]+v_p[1];
                if(sum_p < mx_sum || v_p[0] > v[0]) {
                    r = m-1;
                }
                else {
                    l = m;
                }
            }
            i = l;
        }
    }
	return 0;
}

/*
5
2 2 2 1 2

8
3 3 2 3 3 2 1 3

sample:
8
3 2 3 1 3 3 2 3


*/

• Subtask 1: 20 / 20
• Subtask 2: 70 / 80