2016校赛网络赛E删除字符

建立一张字母表

#include<bits/stdc++.h>
using namespace std;
const long long maxn = 10000+5;
string s1, s2;
int main()
{
	while (cin >> s1 >> s2) {
		int t[maxn];
		string ans = ""; 
		memset(t, 0, sizeof(t));
		for (int i = 0; i < s2.length(); i++) 
			t[s2[i]]++;
		for (int i = 0; i < s1.length(); i++) {
			if (t[s1[i]] == 0)
				ans += s1[i];
		}
		if (ans == "")
			cout << "EMPTY" << endl;
		else
			cout << ans << endl; 
	}
	return 0;
}