Disk tower

 Problem:-

Your task is to construct a tower in $N$ days by following these conditions:

• Every day you are provided with one disk of distinct size.
• The disk with larger sizes should be placed at the bottom of the tower.
• The disk with smaller sizes should be placed at the top of the tower.

The order in which tower must be constructed is as follows:

• You cannot put a new disk on the top of the tower until all the larger disks that are given to you get placed.

Print $N$ lines denoting the disk sizes that can be put on the tower on the $i^{th}$ day.

Input format

• First line: $N$ denoting the total number of disks that are given to you in the $N$ subsequent days
• Second line: $N$ integers in which the $i^{th}$ integers denote the size of the disks that are given to you on the $i^{th}$ day

Note: All the disk sizes are distinct integers in the range of  $1toN$.

Output format

Print $N$ lines. In the $i^{th}$ line, print the size of disks that can be placed on the top of the tower in descending order of the disk sizes.

If on the $i^{th}$ day no disks can be placed, then leave that line empty.

Constraints

$1\le N\le {10}^6$

$1\le sizeofadisk\le N$

Sample Input

5
4 5 1 2 3

Sample Output

 
5 4
 
 
3 2 1

Time Limit: 1

Memory Limit: 256

Source Limit:

Explanation

On the first day, the disk of size 4 is given. But you cannot put the disk on the bottom of the tower as a disk of size 5 is still remaining.

On the second day, the disk of size 5 will be given so now disk of sizes 5 and 4 can be placed on the tower. 

On the third and fourth day, disks cannot be placed on the tower as the disk of 3 needs to be given yet. Therefore, these lines are empty. 

On the fifth day, all the disks of sizes 3, 2, and 1 can be placed on the top of the tower.

Solution:-

#include<stdio.h>

int main()

{

long int n,a[1000000]={0},ind,i,max;

scanf("%ld",&n);

max=n;

for(i=0;i<n;i++)

{

scanf("%ld",&ind);

a[ind]=ind;

if(ind==max)

{

while(a[ind]!=0)

{

printf("%ld ",a[ind]);

ind--;

}

max=ind;

printf("\n");

}

else

printf("\n");

}

return 0;

}