hdu 1159 Common Subsequence(最长公共子序列 DP)

A subsequence of a given sequence is the given sequence
with some elements (possible none) left out. Given a sequence X = <x1, x2,
…, xm> another sequence Z = <z1, z2, …, zk> is a subsequence of X
if there exists a strictly increasing sequence <i1, i2, …, ik> of
indices of X such that for all j = 1,2,…,k, xij = zj. For example, Z = <a,
b, f, c> is a subsequence of X = <a, b, c, f, b, c> with index sequence
<1, 2, 4, 6>. Given two sequences X and Y the problem is to find the
length of the maximum-length common subsequence of X and Y.
The program
input is from a text file. Each data set in the file contains two strings
representing the given sequences. The sequences are separated by any number of
white spaces. The input data are correct. For each set of data the program
prints on the standard output the length of the maximum-length common
subsequence from the beginning of a separate line.

 #include <iostream>

 #include <cstdio>

 #include <cstring>
using namespace std;
int dp[][];
int main()

 {


 char a[],b[];<br/>
 while (~scanf(&#34;%s%s&#34;,a,b))<br/>
 {<br/>
     int len1=strlen(a);<br/>
     int len2=strlen(b);<br/>
     memset(dp,,sizeof(dp));<br/>
     for (int i=len1-;i&gt;=;i--)<br/>
     {<br/>
         for (int j=len2-;j&gt;=;j--)<br/>
         {<br/>
             if (a[i]==b[j])<br/>
                 dp[i][j]=dp[i+][j+]+;<br/>
             else<br/>
                 dp[i][j]=max(dp[i+][j],dp[i][j+]);<br/>
         }<br/>
     }<br/>
     printf (&#34;%d\n&#34;,dp[][]);<br/>
 }<br/>
 return ;<br/>


}