Submission #705766

#	Time	Username	Problem	Language	Result	Execution time	Memory
705766		Abrar_Al_Samit	The Big Prize (IOI17_prize)	C++17	100 / 100	71 ms	11344 KiB

prize

#include<bits/stdc++.h>
#include "prize.h"
using namespace std;
 
const int nax = 2e5 + 1;
vector<vector<int>>mem(nax, vector<int>(2, -1));

vector<int>ASK(int i) {
	if(mem[i][0]==-1) {
		mem[i] = ask(i);
	}
	return mem[i];
}
int find_best(int n) {
 
	int sq = min(n, 500);
	int mx = -1, id;
 
	int cnt = 0;
 
	auto up = [&] () {
		++cnt;
		if(cnt>10000) assert(false);
	};
	vector<int>prv;
	for(int i=0; i<sq; ++i) {
		up();
		auto v = ASK(i);
		if(v[0]+v[1]==0) {
			return i;
		}
		if(v[0]+v[1]>mx) {
			mx = v[0] + v[1];
			id = i;
			prv = v;

			if(mx*mx>n) break;
		}
	}
 
	while(id<n-1) {
		int to = min(n-1, id+sq);
		up();
		auto cr = ASK(to);
		if(cr[0]==prv[0] && cr[1]==prv[1]) {
			id = to;
			continue;
		}
		int l = 0, r = to-id;
		while(l<r) {
			int mid = (l+r+1)/2;
			up();
			cr = ASK(id+mid);
			if(cr[0]==prv[0] && cr[1]==prv[1]) {
				l = mid;
			} else {
				r = mid-1;
			}
		
		}
		id += l+1;
		while(id<n) {
			up();
			cr = ASK(id);
			if(cr[0]+cr[1]==0) {
				return id;
			}
			if(cr[0]+cr[1]==mx) {
				prv = cr;
				break;
			}
			++id;
		}
	}
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:25:13: warning: control reaches end of non-void function [-Wreturn-type]
   25 |  vector<int>prv;
      |             ^~~
prize.cpp:42:23: warning: 'id' may be used uninitialized in this function [-Wmaybe-uninitialized]
   42 |   int to = min(n-1, id+sq);
      |                     ~~^~~

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