POJ2955（区间dp）

#include<bits/stdc++.h>
#define x first
#define y second
#define PB push_back
#define mst(x,a) memset(x,a,sizeof(x))
#define all(a) begin(a),end(a)
#define rep(x,l,u) for(ll x=l;x<u;x++)
#define rrep(x,l,u) for(ll x=l;x>=u;x--)
#define IOS ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
typedef unsigned long long ull;
typedef pair<int,int> PII;
typedef pair<long,long> PLL;
typedef pair<char,char> PCC;
typedef long long ll;
const int N=110;
const int M=1e6+10;
const int INF=0x3f3f3f3f;
const int MOD=1e9+7;
char str[N];
int f[N][N];
void solve(){
    string s;
    while(cin>>s){
        mst(f,0);
        if(s=="end") break;
        int n=(int) s.size();
        rep(i,1,n+1){
            str[i]=s[i-1];
            f[i][i]=0;
        }
        rep(len,2,n+1){
            rep(l,1,n-len+2){
                int r=len+l-1;
                if(str[l]=='(' && str[r]==')' || str[l]=='[' &&str[r]==']'){
                    f[l][r]=f[l+1][r-1]+2;
                }
                rep(k,l,r){
                    f[l][r]=max(f[l][r],f[l][k]+f[k+1][r]);
                }
            }
        }
        cout<<f[1][n]<<endl;
    }
}
int main(){
    IOS;
    solve();
    return 0;
}