Submission #790695

#	Time	Username	Problem	Language	Result	Execution time	Memory
790695		ttamx	The Big Prize (IOI17_prize)	C++14	20 / 100	5 ms	5072 KiB

prize

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

using namespace std;

const int N=2e5+5;

struct fenwick{
	int t[N];
	void add(int i,int v){
		while(i<N)t[i]+=v,i+=i&-i;
	}
	int read(int i){
		int res=0;
		while(i>0)res+=t[i],i-=i&=-i;
		return res;
	}
}f;

int cnt=0;
int n;
int ans=-1;
vector<vector<int>> mem(N);

vector<int>& ask2(int x){
	if(mem[x].empty()){
		assert(++cnt<=1e4);
		mem[x]=ask(x);
	}
	return mem[x];
}

void bsearch(){
	int l=0,r=n-1;
	while(l<r){
		int m=(l+r)/2;
		auto &res=ask2(m);
		if(res[0]+res[1]==0)return void(ans=m);
		if(res[0]){
			res[0]--;
			r=m-1;
		}else{
			res[1]--;
			l=m+1;
		}
	}
	auto &res=ask2(l);
	if(res[0]+res[1]==0)return void(ans=l);
}

int find_best(int _n) {
	n=_n;
	int l=0,r=n-1;
	while(ans==-1)bsearch();
	return ans;
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:53:6: warning: unused variable 'l' [-Wunused-variable]
   53 |  int l=0,r=n-1;
      |      ^
prize.cpp:53:10: warning: unused variable 'r' [-Wunused-variable]
   53 |  int l=0,r=n-1;
      |          ^

• Subtask 1: 20 / 20
• Subtask 2: 0 / 80