Algorithm
Problem Name: 754. Reach a Number
You are standing at position 0 on an infinite number line. There is a destination at position target.
You can make some number of moves numMoves so that:
- On each move, you can either go left or right.
- During the
ithmove (starting fromi == 1toi == numMoves), you takeisteps in the chosen direction.
Given the integer target, return the minimum number of moves required (i.e., the minimum numMoves) to reach the destination.
Example 1:
Input: target = 2 Output: 3 Explanation: On the 1st move, we step from 0 to 1 (1 step). On the 2nd move, we step from 1 to -1 (2 steps). On the 3rd move, we step from -1 to 2 (3 steps).
Example 2:
Input: target = 3 Output: 2 Explanation: On the 1st move, we step from 0 to 1 (1 step). On the 2nd move, we step from 1 to 3 (2 steps).
Constraints:
-109 <= target <= 109target != 0
Code Examples
#1 Code Example with Javascript Programming
Code -
Javascript Programming
const reachNumber = function(target) {
const tar = Math.abs(target);
let step = 0;
let sum = 0;
while (sum < tar) {
step++;
sum += step;
}
while ((sum - tar) % 2 !== 0) {
step++;
sum += step;
}
return step;
};
Input
target = 2
Output
3
#2 Code Example with Python Programming
Code -
Python Programming
class Solution:
def reachNumber(self, target):
pos, step, target = 0, 0, abs(target)
while pos < target or (pos - target) % 2:
step += 1
pos += step
return step
Input
target = 2
Output
3