模板：LCS（最长公共子序列）

 #include <cstring>

 #define max(a,b) ((a) > (b) ? (a) : (b))

 int same(char ch1,char ch2)
 {
     if(ch1 == ch2) return ;
     else return ;
 }

 int LCS(char *str1,char *str2,int len1,int len2)
 {
     int i,j;

     if(len1 < len2) {char *str3 = str1;str1 = str2;str2 = str3;}

     int **dp = new int*[];
     for(i = ; i < ; ++i) dp[i] = new int[len2 + ];
     memset(dp[],,sizeof(int) * (len2 + ));
     dp[][] = ;

     for(i = ; i <= len1; ++i)
     {
         for(j = ; j <= len2; ++j)
         {
             dp[i % ][j] = max(dp[(i - ) % ][j],max(dp[i % ][j - ],dp[(i - ) % ][j - ] + same(str1[i - ],str2[j - ])));
             //cout<<"dp[" << i << "][" << j << "]=" << dp[i % 2][j] << endl;
         }
     }
     int max = dp[len1 % ][len2];

     for(i = ; i < ; ++i) delete [] dp[i];
     delete [] dp;

     return max;
 }