虽然简洁度跟佳爷完全没法比，至少accepted很开心了

 

#include <iostream>

#include <string>

using namespace std;

const int maxd = 100003;

char text[maxd];

int mynext[maxd];

void init(int len)

{

 for (int i = 0;i < len;i++)

  mynext[i] = i+1;

 mynext[len] = -1;

}

int main(void)

{

 //read

 string str;

 while (cin >> str)

 {

  //init next[]

  int len=0;

  while (str[len] == '['||str[len] == ']'&&str[len] == '\0')len++;

  str = str.substr(len);

  len = str.length();

  init(len);

  //core

  int old_tail=0;//承接下文,初始化0处理[]happy类似情况

  for (int i = 0;i < len;i++)

  {

   if (str[i] != '['&&str[i] != ']')old_tail = i + 1;

   else if (str[i] == '[' && (str[i + 1] != '[' && str[i+1] != ']'&& str[i+1]!='\0'))

   {

    mynext[old_tail] = -1;

    int old_head = mynext[0];

    mynext[0] = i + 1 + 1;//str[i+1]为第一个输出字符

    int j;

    for (j = i + 2;str[j] != '['&&str[j] != ']'&&str[j] != '\0';j++);

    mynext[j] = old_head;//str[old_head-1]输出的前一个字符为str[j-1]

    i = j-1;//跳过插进前面的字符

   }

   else if(str[i]==']' && (str[i + 1] != '[' && str[i + 1] != ']' && str[i + 1] != '\0'))

   {

    mynext[old_tail] = i + 1 + 1;

   }

  }

  mynext[old_tail] = -1;

  //output

  for (int i = mynext[0];i != -1;i=mynext[i])

   putchar(str[i-1]);

  putchar('\n');

 }

 

 return 0;

}