Increasing Array

def main() :
    input()
    arr = [int(i) for i in input().split(' ')]
    turns = 0
    for i in range (1, len(arr)) :
        diff= arr[i-1] - arr[i]
        if diff > 0 :
            turns += diff
            arr[i] = arr[i-1]
    print(turns)

if __name__ == "__main__":
    main()

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED