POJ2955：Brackets(区间DP)

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 #define pf(x) printf("%d\n", x)
 6 #define CL(x, y) memset(x, y, sizeof(x))
 7 #define max(a, b) (a > b ? a : b)
 8 using namespace std;
 9 const int MAX = 105;
10 char str[105];
11 int length, dp[MAX][MAX];
12 bool match(char i, char j);
13 int main()
14 {
15     while(gets(str) && strcmp(str, "end"))
16     {
17         int i, j, k, m;
18         length = strlen(str);
19         CL(dp, 0);
20         for(i = 0; i < length; i++)
21         {
22             if(match(str[i], str[i+1]))
23                 dp[i][i+1] = 1;
24         }
25         for(k = 2; k < length; k++)
26             for(i = 0; i < length-k; i++)
27             {
28                 j = i+k;
29                 if(match(str[i], str[j]))
30                     dp[i][j] = dp[i+1][j-1]+1;
31                 for(m = 0; m < k; m++)
32                     dp[i][j] = max(dp[i][j], dp[i][i+m] + dp[i+m+1][j]);
33             }
34         pf(dp[0][length-1]*2);
35     }
36     return 0;
37 }
38 bool match(char i, char j)
39 {
40     if(i==‘(‘ && j==‘)‘)
41         return true;
42     if(i==‘[‘ && j==‘]‘)
43         return true;
44     else
45         return false;
46 }
47 //  gets(str) 包括空格
48 //  cin 则不存在
49 //  string str;     str.size()代表长度
50 //  const int maxn = 110;