[poj2955]括号匹配(区间dp)

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 #include<cstdlib>
 5 #include<cmath>
 6 #include<iostream>
 7 using namespace std;
 8 typedef long long ll;
 9 int dp[202][202];
10 int main(){
11     string s;
12     ios::sync_with_stdio(0);
13     while(cin>>s){
14         memset(dp,0,sizeof dp);
15         if(s=="end") break;
16         for(int len=1;len<=s.size();len++){
17             for(int l=0,r;(r=l+len-1)<s.size();l++){
18                 if((s[l]==‘(‘&&s[r]==‘)‘)||(s[l]==‘[‘&&s[r]==‘]‘)) dp[l][r]=dp[l+1][r-1]+2;
19                 for(int i=0;i<r;i++) dp[l][r]=max(dp[l][i]+dp[i+1][r],dp[l][r]);
20             }
21         }
22         cout<<dp[0][s.size()-1]<<"\n";
23     }
24     return 0;
25 }