Google | Onsite | Microwave optimal keystroke input

Round 1

Questions: Given that microwave takes key stroke inputs, a target cooking time and the following costs for input, find optimal input:

• Input 999 will be interpreted as 9 minutes 99 seconds, 81 as 81 seconds, 1221 as 12 minutes 21 seconds.
• Cost of each key stroke is 1, cost of moving the finger to a different key is 2 || 999 cost is 3, 1122 cost is 6, 1234 cost is 10.
• Input has to be within 10% of target time. If the cost is same, select the input that's closest to the target.
• Ex: for target time of 10 minutes, 888 is optimal (not 999).