【POJ】1141 Brackets Sequence

经典DP问题，注意输入不要使用while(xxx != EOF)，否则WA，测试数据只有一组。同样的测试数据可能有多种答案。但最小长度唯一。一定不能用while，切记。

#include <iostream>
using namespace std;
#include <string>

#define MAXNUM 200
#define MAXVAL 32767

string match(char []);

int main() {
    string regstr;
    char str[MAXNUM];

    cin >>str;
    regstr = match(str);
    cout <<regstr<<endl;

    return 0;
}

string match(char str[]) {
    string regstr[MAXNUM][MAXNUM];
    int add[MAXNUM][MAXNUM];
    int len = strlen(str);
    int i, j, k;

    memset(add, 0, sizeof(add));

    for (i=0; i<len; i++)
        for (j=i; j<len; j++)
        {
            add[i][j] = MAXVAL;
            regstr[i][j] = "";
        }

    for (i=len-1; i>=0; i--) {
        for (j=i; j<len; j++) {
            if (j == i) {
                add[i][j] = 1;
                if (str[i] == '(' || str[i] == ')')
                    regstr[i][j] = "()";
                if (str[i] == '[' || str[i] == ']')
                    regstr[i][j] = "[]";
            } else {if (str[i] == '(' && str[j] == ')') {
                    add[i][j] = add[i+1][j-1];
                    regstr[i][j] = "(" + regstr[i+1][j-1] + ")";
                } else if (str[i] == '[' && str[j] == ']') {
                    add[i][j] = add[i+1][j-1];
                    regstr[i][j] = "[" + regstr[i+1][j-1] + "]";
                }

                for (k=i; k<j; k++) {
                    if (add[i][k]+add[k+1][j] < add[i][j]) {
                        add[i][j] = add[i][k] + add[k+1][j];
                        regstr[i][j] = regstr[i][k] + regstr[k+1][j];
                    }
                }
            }
        }
    }

    return regstr[0][len-1];
}