poj 1159 (DP LCS)
滚动数组 + LCS
1 // File Name: 1159.cpp 2 // Author: Missa_Chen 3 // Created Time: 2013年07月08日 星期一 10时07分13秒 4 5 #include <iostream> 6 #include <string> 7 #include <algorithm> 8 #include <cstdio> 9 #include <cstring> 10 #include <cmath> 11 #include <queue> 12 #include <map> 13 #include <stack> 14 #include <set> 15 #include <cstdlib> 16 #include <vector> 17 #include <time.h> 18 19 using namespace std; 20 21 const int maxn = 5e3 + 5; 22 int n; 23 char buf[maxn]; 24 int LCS(string s1, string s2) 25 { 26 int dp[2][maxn] = {0}; 27 int e = 0; 28 for (int i = 1; i <= n; ++i) 29 { 30 e = 1 - e; 31 for (int j = 1; j <= n; ++j) 32 if (s1[i - 1] == s2[j - 1]) 33 dp[e][j] = dp[1 - e][j - 1] + 1; 34 else dp[e][j] = max (dp[1 - e][j], dp[e][j - 1]); 35 } 36 return dp[e][n]; 37 } 38 int main() 39 { 40 while (~scanf("%d",&n)) 41 { 42 scanf("%s", buf); 43 string s, rev; 44 s = rev = buf; 45 reverse(rev.begin(), rev.end()); 46 printf("%d\n", n - LCS(s, rev)); 47 } 48 return 0; 49 }
