最长公共子序列

[cpp] view plaincopy

    #include <stdio.h>  
    #include <string.h>  
    #include <algorithm>  
    using namespace std;  
      
    char s1[1000],s2[1000];  
    int len1,len2,dp[1000][1000],mark[1000][1000];//假设数据太大，dp数组能够考虑滚动数组  
      
    void LCS()  
    {  
        int i,j;  
        memset(dp,0,sizeof(dp));  
        for(i = 0;i<=len1;i++)  
        mark[i][0] = 1;  
        for(i = 0;i<=len2;i++)  
        mark[0][i] = -1;  
        for(i = 1; i<=len1; i++)  
        {  
            for(j = 1; j<=len2; j++)  
            {  
                if(s1[i-1]==s2[j-1])  
                {  
                    dp[i][j] = dp[i-1][j-1]+1;  
                    mark[i][j] = 0;  
                }  
                else if(dp[i-1][j]>=dp[i][j-1])  
                {  
                    dp[i][j] = dp[i-1][j];  
                    mark[i][j] = 1;  
                }  
                else  
                {  
                    dp[i][j] = dp[i][j-1];  
                    mark[i][j] = -1;  
                }  
            }  
        }  
    }  
      
    void PrintLCS(int i,int j)  
    {  
        if(!i && !j)  
        return ;  
        if(mark[i][j]==0)//公共的  
        {  
            PrintLCS(i-1,j-1);  
            printf("%c",s1[i-1]);  
        }  
        else if(mark[i][j]==1)  
        {  
            PrintLCS(i-1,j);  
            printf("%c",s1[i-1]);  
        }  
        else  
        {  
            PrintLCS(i,j-1);  
            printf("%c",s2[j-1]);  
        }  
    }