破损的键盘（UVa 11988）

　　s[] 数组用来保存原有的字符序列

　　nex[] 数组记录打印的下标顺序

C++11 代码如下：

#include<iostream>
#include<cstring>
using namespace std;
#define maxn 100006
char s[maxn];
int nex[maxn], n;

int main() {
    while (cin >> s + 1) {
        int cur = 0, last = 0;
        nex[0] = 0;
        char ch;    
        for (int i = 1; i <=strlen(s + 1); i++) {
            ch = s[i];
            if (ch == '[') cur = 0;
            else if (ch == ']') cur = last;
            else {
                nex[i] = nex[cur];
                nex[cur] = i;
                if (cur == last)last = i;
                cur = i;
            }
        }
        for (int i = nex[0]; i != 0; i = nex[i])
            cout << s[i];
        cout << endl;
    }
    return 0;
}