poj 2629 Common permutation

Common permutation

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 5059		Accepted: 1519

Description

Given two strings of lowercase letters, a and b, print the longest string x of lowercase letters such that there is a permutation of x that is a subsequence of a and there is a permutation of x that is a subsequence of b.

Input

Input consists of pairs of lines. The first line of a pair contains a and the second contains b. Each string is on a separate line and consists of at most 1,000 lowercase letters.

Output

For each subsequent pair of input lines, output a line containing x. If several x satisfy the criteria above, choose the first one in alphabetical order.

Sample Input

pretty
women
walking
down
the
street

Sample Output

e
nw
et

#include<iostream>
#include<algorithm>
using namespace std;

int comp(char &a,char &b)
{
    return a<b;
}

int main()
{
    char a[1001];
    char b[1001];
    int i,j;
    int lena,lenb;
    int pos;
    while(gets(a) && gets(b))
    {
        lena=strlen(a);
        lenb=strlen(b);
        sort(a,a+lena,comp);
        sort(b,b+lenb,comp);
        pos=-1;
        for(i=0;i<lena;i++)
        {
            for(j=pos+1;j<lenb;j++)
            {
                if(a[i]==b[j])
                {
                    pos=j;
                    cout<<a[i];
                    break;
                }
            }
        }
        cout<<endl;
    }
    return 0;
}