[DP]hit1603

http://acm.hit.edu.cn/hoj/problem/view?id=1603

备忘录式dp，然后递归输出结果：

#include<iostream>
#include<cstdio>
#include<iomanip>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;
#define rep(i,n,m) for(int i=(n);i<=(m);++i)
#define re1(i,n) rep(i,1,n)
#define re0(i,n) rep(i,0,n)
const int maxnum=100+1;
const int maxint=2147483647;
char a[maxnum];
int dp[maxnum][maxnum];
char add[maxnum][maxnum];
int work(int i,int j){
	int &ans=dp[i][j];
	if(ans!=-1)
		return ans;
	if(i>j)
		return ans=0;
	if(i==j)
		return ans=1;
	ans=maxint;
	if(a[i]=='(' && a[j]==')' || a[i]=='[' && a[j]==']'){
		add[i][j]=-1;
		ans = work(i+1,j-1);
	}
	rep(k,i,j-1){
		int t = work(i,k)+work(k+1,j);
		if(t<ans){
			ans=t;
			add[i][j]=k;
		}
	}
	return ans;
}
void make(int i,int j){
	if(i>j)
		return;
	if(i==j){
		if(a[i]=='(' || a[i]==')')
			printf("()");
		else
			printf("[]");
	}else{
		if(add[i][j]==-1){
			printf("%c",a[i]);
			make(i+1,j-1);
			printf("%c",a[j]);
		}else{
			make(i,add[i][j]);
			make(add[i][j]+1,j);
		}
	}
}
int main(){
	while(~scanf("%s",a)){
		int la=strlen(a);
		re0(u,la-1)re0(w,la-1){
			dp[u][w]=-1;
			add[u][w]=-2;
		}
		work(0,la-1);
		make(0,la-1);
		puts("");
	}
}