洛谷P2249 【深基13.例1】查找

#include <iostream>

using namespace std;

const int N=1000010;
int arr[N];

int main()
{
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		cin>>arr[i];
	}
	while(m--)
	{
		int x;
		cin>>x;
		int left=1;
		int right=n;
		while(left<right)
		{
			int middle=left+(right-left)/2;
			if(arr[middle]>=x) right=middle;
			else left=middle+1;
		}
		if(arr[left]==x) cout<<left<<' ';
		else cout<<-1<<' ';
	}
	return 0;
}