Increasing Array

import sys




def main():
    
    n = input()
    s = input()

    a = s.split()
    a = list(map(lambda x: int(x), a))

    r = 0

    prev_inc = a[0]
    for i in range(1, len(a)):
        current_val = a[i]
        if a[i] < prev_inc:
            c = prev_inc - a[i]
            r += c
            prev_inc = a[i] + c
        else:
            prev_inc = a[i]
    print(r)


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