poj 1159 (DP LCS)

滚动数组 + LCS

 // File Name: 1159.cpp
 // Author: Missa_Chen
 // Created Time: 2013年07月08日 星期一 10时07分13秒

 #include <iostream>
 #include <string>
 #include <algorithm>
 #include <cstdio>
 #include <cstring>
 #include <cmath>
 #include <queue>
 #include <map>
 #include <stack>
 #include <set>
 #include <cstdlib>
 #include <vector>
 #include <time.h>

 using namespace std;

 const int maxn = 5e3 + ;
 int n;
 char buf[maxn];
 int LCS(string s1, string s2)
 {
     int dp[][maxn] = {};
     int e = ;
     for (int i = ; i <= n; ++i)
     {
         e =  - e;
         for (int j = ; j <= n; ++j)
             if (s1[i - ] == s2[j - ])
                 dp[e][j] = dp[ - e][j - ] + ;
             else dp[e][j] = max (dp[ - e][j], dp[e][j - ]);
     }
     return dp[e][n];
 }
 int main()
 {
     while (~scanf("%d",&n))
     {
         scanf("%s", buf);
         string s, rev;
         s = rev = buf;
         reverse(rev.begin(), rev.end());
         printf("%d\n", n - LCS(s, rev));
     }
     return ;
 }