Increasing Array

Explanation

In this problem, we are provided with an array containing n positive integers. Our task is to make this array non-decreasing by only applying the following move minimum number of times.

Move: Add 1 to any element of the array.

This can be done by comparing arr[i] and arr[i - 1] where i ranges from 1 to n - 1. If arr[i] is less than arr[i - 1] we will add 1 to arr[i] arr[i - 1] - arr[i] times.

We'll add arr[i - 1] - arr[i] to a moves variable everytime we perform this.

Code

n = int(input())
arr = list(map(int, input().split()))

moves = 0

for i in range(1, n):
    if arr[i] < arr[i - 1]:
        moves += arr[i - 1] - arr[i]
        arr[i] = arr[i - 1]

print(moves)