zoj 2704 Brackets

输出最长的配对序列，brackets—括号

忘了当时怎么讨论的了，总之用栈来存储

序列的对应的标号，标号差值与序列的长

度相关，然后从small 到big输出，只知道

当时很纠结

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>

#define maxn 100000

char target[maxn+10];
int stack[maxn+10];

int top;                         //栈顶的元素的下标 

void push(int x)                 //入栈 
{
   stack[top] = x;
}

void pop()                       //出栈 
{
   stack[top] = 0;
}

int match(int m,int n)           //检查是否匹配 
{
    if(target[ stack[m] ] == '(' && target[n] == ')')
        return 1;
    if(target[ stack[m] ] == '[' && target[n] == ']')
        return 1;
    else 
      return 0;
}


int main()
{
     int i,len,max,big,small;
     
    
     while(scanf("%s",target)==1)
     {
	 len = strlen(target);
	 top = 0;
	 push(len);                   //栈底元素，判断栈是否为空
	 top = 1;
         push(0);                   //target的首号元素下标 
         for(i=1;i<len;i++)
	 {
	    if(match(top,i))
	    {
		pop();
		top--;
	    }
	    else
	    {
		top++;
		push(i);
	    }
         }
	  if(top == 0)
	     printf("%s\n\n",target);
	  else if(top == len)
	     printf("\n\n");
	  else if(top>0&&top<len)
	  {
             stack[0] = -1;
             max = 0;
             big = 0;
             small = 0;
             int m;
             stack[top+1] = len;
             for(i=1;i<=top+1;i++)
             {
		if((m = stack[i] - stack[i-1]) > max)
		{
		    max = m;
		    big = stack[i];
		    small = stack[i-1];
		}
	     }
	     for(i=small+1;i<big;i++)
	       printf("%c",target[i]); 
	     printf("\n\n");
	  }
	  
     } 
     return 0;
}