Algorithm
Problem Name: 991. Broken Calculator
Problem Link: https://leetcode.com/problems/broken-calculator/
There is a broken calculator that has the integer startValue on its display initially. In one operation, you can:
- multiply the number on display by
2, or - subtract
1from the number on display.
Given two integers startValue and target, return the minimum number of operations needed to display target on the calculator.
Example 1:
Input: startValue = 2, target = 3
Output: 2
Explanation: Use double operation and then decrement operation {2 -> 4 -> 3}.
Example 2:
Input: startValue = 5, target = 8
Output: 2
Explanation: Use decrement and then double {5 -> 4 -> 8}.
Example 3:
Input: startValue = 3, target = 10
Output: 3
Explanation: Use double, decrement and double {3 -> 6 -> 5 -> 10}.
Constraints:
1 <= startValue, target <= 109
Code Examples
#1 Code Example with Java Programming
Code -
Java Programming
class Solution {
public int brokenCalc(int startValue, int target) {
int numOfSteps = 0;
while (target > startValue) {
numOfSteps++;
if (target % 2 == 1) {
target++;
} else {
target /= 2;
}
}
return numOfSteps + startValue - target;
}
}
Input
startValue = 2, target = 3
Output
2
#2 Code Example with Python Programming
Code -
Python Programming
class Solution:
def brokenCalc(self, X, Y):
res = 0
while X < Y:
res += Y % 2 + 1
Y = (Y + 1) // 2
return res + X - Y
Input
startValue = 2, target = 3
Output
2