1050. String subtraction (20)-pat

1050. String subtraction (20) Time limit 10 ms memory limit 32000 kb code length limit 16000 B discriminant program standard

Given two strings s_{1 and S2, s = s1-S2 is defined to be the remaining string after taking all the characters in S2 from
S1. Your task is simply to calculate s1-S2 for any given strings. However, it might not be that simple to do itFast.}

Input specification:

Each input file contains one test case. Each case consists of two lines which gives S_{1 and S2, 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-S2 in one line.}

Sample input:

They are students.aeiou

Sample output:

Thy r stdnts.

Recommendation index :※

Source: http://pat.zju.edu.cn/contests/pat-a-practise/1050

Simply think about it.

#include<iostream>#include<string.h>#include<stdio.h>using namespace std;#define  N 128int main(){int i=0,sum;bool is_exist[N];char ch;char str[10000];memset(is_exist,0,sizeof(is_exist));while(scanf("%c",&ch)&&ch!='\n'){is_exist[ch]=true;str[i++]=ch;}sum=i;while(scanf("%c",&ch)&&ch!='\n'){is_exist[ch]=false;}i=0;while(i<sum){if(is_exist[str[i]]!=false)printf("%c",str[i]);i++;}return 0;}