1050 String Subtraction （20 分）

1050 String Subtraction （20 分）

Given two strings S​1​​ and S​2​​, S=S​1​​−S​2​​ is defined to be the remaining string after taking all the characters in S​2​​from S​1​​. Your task is simply to calculate S​1​​−S​2​​ for any given strings. However, it might not be that simple to do it fast.

Input Specification:

Each input file contains one test case. Each case consists of two lines which gives S​1​​ and S​2​​, respectively. The string lengths of both strings are no more than 10​4​​. It is guaranteed that all the characters are visible ASCII codes and white space, and a new line character signals the end of a string.

Output Specification:

For each test case, print S​1​​−S​2​​ in one line.

Sample Input:

They are students.
aeiou

Sample Output:

Thy r stdnts.

 

分析：散列，水题，用map映射比较快

 1 /**
 2 * Copyright(c)
 3 * All rights reserved.
 4 * Author : Mered1th
 5 * Date : 2019-02-25-21.03.43
 6 * Description : A1050
 7 */
 8 #include<cstdio>
 9 #include<cstring>
10 #include<iostream>
11 #include<cmath>
12 #include<algorithm>
13 #include<string>
14 #include<unordered_set>
15 #include<map>
16 #include<vector>
17 #include<set>
18 using namespace std;
19 
20 int main(){
21 #ifdef ONLINE_JUDGE
22 #else
23     freopen("1.txt", "r", stdin);
24 #endif
25     string a,b;
26     getline(cin,a);
27     getline(cin,b);
28     map<char,int> mp;
29     for(int i=0;i<b.length();i++){
30         mp[b[i]]++;
31     }
32     for(int i=0;i<a.length();i++){
33         if(mp[a[i]]==0){
34             printf("%c",a[i]);
35         }
36     }
37     return 0;
38 }

 

转载于:https://www.cnblogs.com/Mered1th/p/10433455.html