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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#212840#1011. 双倍查找sycwhxJudgement Failed//C++449b2024-10-20 11:59:502024-10-20 12:00:01

answer

#include<bits/stdc++.h>	
using namespace std;
typedef long long ll;
ll n,m,x,cnt,a[100005];

bool bs(ll l,ll r,ll x)
{
	ll mid;
	while(l<=r)
	{
		mid=(l+r)/2;
		if(a[mid]==x)
			return true;
		else if(a[mid]>x)
			r=mid-1;
		else
			l=mid+1;
	}
	return false;
}

int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
		cin>>a[i];
	sort(a+1,a+n+1);
	for(int i=1;i<=n;i++)
		if(bs(1,n,2*a[i]))
			cnt++;
	cout<<cnt;
	return 0;
}

详细

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