Codechef•May 25, 2025

Minimum number of coins

Hazrat Ali

Codechef

Find the minimum number of coins Chef needs, to pay exactly X rupees. If it is impossible to pay  X rupees in denominations of rupees 5 and 10 only, print −1.

Input Format

  • First line will contain TT, number of test cases. Then the test cases follow.
  • Each test case contains of a single integer XX.

Output Format

For each test case, print a single integer - the minimum number of coins Chef needs, to pay exactly XX rupees. If it is impossible to pay XX rupees in denominations of rupees 5 and 10 only, print −1.

Constraints

  • 1≤T≤1000
  • 1≤X≤1000

Subtasks

  • Subtask 1 (100 points): Original constraints.

Sample 1:

Input 
3
50
15
8
Output
5
2
-1

Solution
for _ in range(int(input())):
    n=int(input())
    coin=int(n/10)
    coin2=n-coin*10
    coin3=int(coin2/5)
    sol=n-coin3*5-coin*10
    if sol>0:
        print(-1)
    else:
        print(coin3+coin)

 

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