BNUOJ 1260 Brackets Sequence

Brackets Sequence

Time Limit: 1000ms

Memory Limit: 65536KB

This problem will be judged on PKU. Original ID: 1141
64-bit integer IO format: %lld      Java class name: Main

Special Judge

 

Let us define a regular brackets sequence in the following way: 

1. Empty sequence is a regular sequence. 
2. If S is a regular sequence, then (S) and [S] are both regular sequences. 
3. If A and B are regular sequences, then AB is a regular sequence. 

For example, all of the following sequences of characters are regular brackets sequences: 

(), [], (()), ([]), ()[], ()[()] 

And all of the following character sequences are not: 

(, [, ), )(, ([)], ([(] 

Some sequence of characters '(', ')', '[', and ']' is given. You are to find the shortest possible regular brackets sequence, that contains the given character sequence as a subsequence. Here, a string a1 a2 ... an is called a subsequence of the string b1 b2 ... bm, if there exist such indices 1 = i1 < i2 < ... < in = m, that aj = bij for all 1 = j = n.

 

Input

The input file contains at most 100 brackets (characters '(', ')', '[' and ']') that are situated on a single line without any other characters among them.

 

Output

Write to the output file a single line that contains some regular brackets sequence that has the minimal possible length and contains the given sequence as a subsequence.

 

Sample Input

([(]

Sample Output

()[()]

Source

Northeastern Europe 2001

 

解题：这dp啊，我这种学渣啊，每做一次，就有一次新的感觉！水好深啊！

 

注意是单样例的！改成多样例，立马WA了

 

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <climits>
#include <vector>
#include <queue>
#include <cstdlib>
#include <string>
#include <set>
#include <stack>
#define LL long long
#define pii pair<int,int>
#define INF 0x3f3f3f3f
using namespace std;
const int maxn = 110;
int dp[maxn][maxn],c[maxn][maxn] = {-1};
char str[maxn];
void print(int i,int j) {
    if(i > j) return;
    if(i == j) {
        if(str[i] == '(' || str[j] == ')')
            printf("()");
        else printf("[]");
    } else {
        if(c[i][j] >= 0) {
            print(i,c[i][j]);
            print(c[i][j]+1,j);
        } else {
            if(str[i] == '(') {
                printf("(");
                print(i+1,j-1);
                printf(")");
            } else {
                printf("[");
                print(i+1,j-1);
                printf("]");
            }
        }
    }
}
void go() {
    int len = strlen(str),i,j,k,theMin,t;
    for(i = 0; i < len; i++) dp[i][i] = 1;
    for(k = 1; k < len; k++) {
        for(i = 0; i+k < len; i++) {
            j = i+k;
            theMin = dp[i][i]+dp[i+1][j];
            c[i][j] = i;
            for(t = i+1; t < j; t++) {
                if(dp[i][t]+dp[t+1][j] < theMin) {
                    theMin = dp[i][t]+dp[t+1][j];
                    c[i][j] = t;
                }
            }
            dp[i][j] = theMin;
            if(str[i] == '(' && str[j] == ')' || str[i] == '[' && str[j] == ']') {
                if(dp[i+1][j-1] < theMin) {
                    dp[i][j] = dp[i+1][j-1];
                    c[i][j] = -1;
                }
            }
        }
    }
    print(0,len-1);
}
int main() {
    scanf("%s",str);
    go();
    puts("");
    return 0;
}