super reduced strings

 Problem:-

Steve has a string of lowercase characters in range ascii[‘a’..’z’]. He wants to reduce the string to its shortest 
length by doing a series of operations. In each operation he selects a pair of adjacent lowercase letters that match, andhe deletes them. For instance, the string aab could be shortened to b in one operation.

Steve’s task is to delete as many characters as possible using this method and print the resulting string. If the final string is empty, print "Empty String" without quotes.

characters can be deleted only if they form a pair and are same(i.e from aaa we can only delete 2 a's and will be left with a single a).

INPUT:

A single string, s.

CONSTRAINTS:

1<=|s|<=1000

OUTPUT:

If the final string is empty, print Empty String; otherwise, print the final non-reducible string.

Sample Input

aaabccddd

Sample Output

abd

Time Limit: 5

Memory Limit: 256

Source Limit:

Explanation

Steve performs the following sequence of operations to get the final string:

aaabccddd ? abccddd ? abddd ? abd

Code:-

#include<stdio.h>

#define max 1000

char stack[max];

int top=-1;

void push(char ch)

{

  top++;

  stack[top]=ch;

}

int main()

{

  char s[1000];

  scanf("%s",s);

  for(int i=0;s[i];i++)

  {

    if(top!=-1 && stack[top]==s[i])

     top--;

    else

     push(s[i]);

  }

  if(top==-1)

   printf("Empty String");

  else{

    for(int i=0;i<=top;i++)

     printf("%c",stack[i]);

  }

  return 0;

}