题解 | #查找#pair对的使用

#include<bits/stdc++.h>
#include<iterator>
using namespace std;
int main(){
	set<int>s;
	vector<int> a;
	//write your code here......
	int n,m;
	cin >> n >> m;
	for(int i = 0; i < n; i++){
		int inPut;
		cin >> inPut;
		s.insert(inPut);
	}
	pair<set<int>::iterator,set<int>::iterator> pair;
	for(int i = 0; i < m; i++){
		int inPut;
		cin >> inPut;
		a.push_back(inPut);
	}
	for(int i = 0; i < m; i++){
		pair = s.equal_range(a[i]);
		if(pair.second != s.end())
			cout << *pair.second << endl;
		else cout << "-1" << endl;
	}
	return 0;
}