HDU 2476 String painter

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 const int maxn = 120;
 4 int dp[maxn][maxn],ans[maxn];
 5 char a[maxn],b[maxn];
 6 int main() {
 7     while(~scanf("%s%s",a,b)) {
 8         int n = strlen(a);
 9         memset(dp,0,sizeof dp);
10         for(int i = n-1; i >= 0; --i)
11             for(int j = i; j < n; ++j) {
12                 dp[i][j] = dp[i+1][j] + 1;
13                 for(int k = i+1; k <= j; ++k) {
14                     if(b[i] == b[k])
15                         dp[i][j] = min(dp[i][j],dp[i+1][k]+dp[k+1][j]);
16                 }
17             }
18         memset(ans,0x3f,sizeof ans);
19         for(int i = 0; i < n; ++i) {
20             if(a[i] == b[i]) ans[i] = i?ans[i-1]:0;
21             else ans[i] = dp[0][i];
22             for(int j = i-1; j >= 0; --j)
23                 ans[i] = min(ans[i],ans[j]+dp[j+1][i]);
24         }
25         printf("%d\n",ans[n-1]);
26     }
27     return 0;
28 }