蒟蒻求助

#include<bits/stdc++.h>
using namespace std;
int n,m,x,a[10001]={};
int main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)cin>>a[i];
	a[0]=-1;
	for(int i=1;i<=m;i++)
	{
		int left=1,right=n,mid;
		cin>>x;
		while(left<right)
		{
			mid=(right-left)/2+left;
			if(a[mid]>=x)right=mid;
			else left=mid+1;
		}
		if(a[left]==x)cout<<left<<" ";
		else cout<<-1<<" ";
	}
	
	return 0;
}

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