[Swift]LeetCode492. 构造矩形 | Construct the Rectangle

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For a web developer, it is very important 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.

You need to output the length L and the width W of the web page you designed in sequence. 

Example:

Input: 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.

 Note:

1. The given area won't exceed 10,000,000 and is a positive integer
2. The web page's width and length you designed must be positive integers.

---

作为一位web开发者， 懂得怎样去规划一个页面的尺寸是很重要的。 现给定一个具体的矩形页面面积，你的任务是设计一个长度为 L 和宽度为 W 且满足以下要求的矩形的页面。要求：

1. 你设计的矩形页面必须等于给定的目标面积。

2. 宽度 W 不应大于长度 L，换言之，要求 L >= W 。

3. 长度 L 和宽度 W 之间的差距应当尽可能小。

你需要按顺序输出你设计的页面的长度 L 和宽度 W。

示例：

输入: 4
输出: [2, 2]
解释: 目标面积是 4， 所有可能的构造方案有 [1,4], [2,2], [4,1]。
但是根据要求2，[1,4] 不符合要求; 根据要求3，[2,2] 比 [4,1] 更能符合要求. 所以输出长度 L 为 2， 宽度 W 为 2。

说明:

1. 给定的面积不大于 10,000,000 且为正整数。
2. 你设计的页面的长度和宽度必须都是正整数。

---

 8ms

class Solution {
    func constructRectangle(_ area: Int) -> [Int] {
        var w = Int(sqrt(Double(area)))
        while area % w != 0 {
            w -= 1
        }
        return [area / w, w]
    }
}

---

8ms

class Solution {
    func constructRectangle(_ area: Int) -> [Int] {
        var minDiff = Int.max
        var minDiffWidth: Int?
        let maxWidth = Int(ceil(sqrt(Double(area))))
        
        for width in 1 ... maxWidth {
            guard area % width == 0 else { continue }
            
            let length = area / width
            if length >= width, length - width < minDiff {
                minDiff = length - width
                minDiffWidth = width
            }
        }
        if let minDiffWidth = minDiffWidth {
            return [area / minDiffWidth, minDiffWidth]
        } else {
            return [area, 1]
        }
    }
}

---

12ms

class Solution {
    func constructRectangle(_ area: Int) -> [Int] {
         let maxW = Int(sqrt(Double(area)))
        var result = [area,1]
         if maxW >= 2 {
            for i in 2...maxW {
                if area % i == 0 {
                    result = [area / i,i]
                }
            }
        }
        return result
    }
}

---

12ms

class Solution {
    func constructRectangle(_ area: Int) -> [Int] {
        var n = Int(sqrt(Double(area)))
        while area % n != 0 {
            n -= 1
        }
        return [max(n, area/n), min(n, area/n)]
    }
}

---

20ms

class Solution {
    func constructRectangle(_ area: Int) -> [Int] {
        var maxW = Int(sqrt(Double(area)))
        var result = [area,1]
        while maxW >= 2 {
            if area % maxW == 0 {
                result = [area / maxW,maxW]
                break
            }
            maxW -= 1
        }       
        return result
    }
}

---

116ms

class Solution {
    func constructRectangle(_ area: Int) -> [Int] {
        guard area > 0 else { return [0, 0] }
        let sqr = sqrt(Double(area))
        var i = Int(sqr)
        var j = Int(sqr)
        var prod = i*j
        while prod != area {
            if prod > area {
                i -= 1
            } else if prod < area {
                j += 1
            }
            prod = i*j
        }
        return [j, i] 
        
    }
}