POJ 2955 Brackets 区间DP

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 char s[200];
 6 int dp[200][200];
 7 int dfs(int x,int y)
 8 {
 9     if (x >= y)
10         return 0;
11     if (dp[x][y] != -1)
12         return dp[x][y];
13     if ((s[x] == ‘(‘ && s[y] == ‘)‘) || (s[x] == ‘[‘ && s[y] == ‘]‘))
14         dp[x][y] = dfs(x + 1,y - 1) + 2;
15     for (int i = x;i <= y - 1;i++)
16         dp[x][y] = max(dp[x][y],dfs(x,i) + dfs(i + 1,y));
17     return dp[x][y];
18 }
19 int main()
20 {
21     while (scanf("%s",s + 1) > 0)
22     {
23         memset(dp,-1,sizeof(dp));
24         if (s[1] == ‘e‘)
25             break;
26         int len = strlen(s + 1);
27         printf("%d\n",dfs(1,len)); 
28     }
29     return 0;
30 }