hdu 1503 最长公共子序列

/*
给两个串a,b。输出一个最短的串(含等于a的子序列且含等于b的子序列)
*/
#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

const int maxn=105;
int dp[maxn][maxn],path[maxn][maxn];
int len,len1,len2;
char text[maxn],a[maxn],b[maxn];

void getpath()
{
    int n=len,i=len1,j=len2;
    while(n)
    {
        if(path[i][j]==0)
            text[n--]=a[i],i--,j--;
        else if(path[i][j]==1) i--;
        else j--;
    }
}

int main()
{
    int i,j,k;
    a[0]=b[0]='0';
    while(~scanf("%s%s",a+1,b+1))
    {
        memset(dp,0,sizeof(dp));
        len1=strlen(a)-1,len2=strlen(b)-1;
        for(i=1;i<=len1;i++)
        {
            for(j=1;j<=len2;j++)
            {
                if(a[i]==b[j])dp[i][j]=dp[i-1][j-1]+1,path[i][j]=0;
                else
                {
                    if(dp[i-1][j]>dp[i][j-1]) dp[i][j]=dp[i-1][j],path[i][j]=1;
                    else dp[i][j]=dp[i][j-1],path[i][j]=2;
                }
            }
        }
        len=dp[len1][len2];
        getpath();
        j=1,k=1;
        for(i=1;i<=len;i++)
        {
            while(a[j]!=text[i]) printf("%c",a[j++]);
            while(b[k]!=text[i]) printf("%c",b[k++]);
            printf("%c",text[i]);
            j++;k++;
        }
        while(j<=len1) printf("%c",a[j++]);
        while(k<=len2) printf("%c",b[k++]);
        printf("\n");
    }
    return 0;
}