Given an array of integers, move all zeros present in the array to the end. The solution should maintain the relative order of items in the array.
Input : [1,3,0,0,4,0,9]
Modify array so that it becomes :[1 3 4 9 0 0 0]
Constraint1 : You are not suppose to use any
Constraint2 : You need to change the same array
with single traversal with O(n) time complexity
Problem level: Easy