Leetcode 492 - Construct the rectangle

Note:

  • Double pointers set as floor(sqrt(area)).
  • Check if left*right === area. If too big, left--, otherwise right++

Question:

A web developer needs to know how to design a web page’s size. So, given a specific rectangular web page’s area, your job by now is to design a rectangular web page, whose length L and width W satisfy the following requirements:

  1. The area of the rectangular web page you designed must equal to the given target area.
  2. The width W should not be larger than the length L, which means L >= W.
  3. The difference between length L and width W should be as small as possible.
    Return an array [L, W] where L and W are the length and width of the web page you designed in sequence.

Example:

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Input: area = 4
Output: [2,2]
Explanation: The target area is 4, and all the possible ways to construct it are [1,4], [2,2], [4,1].
But according to requirement 2, [1,4] is illegal; according to requirement 3, [4,1] is not optimal compared to [2,2]. So the length L is 2, and the width W is 2.

Input: area = 122122
Output: [427,286]

Code:

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/**
* @param {number} area
* @return {number[]}
*/
var constructRectangle = function(area) {
const middle = Math.floor(Math.sqrt(area));
let left = middle, right = middle;
while (left * right !== area) {
const res = left * right;
if (res > area) {
left--;
} else {
right++;
}
}
return [right, left];
};