492-ConstructTheRectangle.go

package main

// 492. Construct the Rectangle
// 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:
//     The area of the rectangular web page you designed must equal to the given target area.
//     The width W should not be larger than the length L, which means L >= W.
//     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 1:
// 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.

// Example 2:
// Input: area = 37
// Output: [37,1]

// Example 3:
// Input: area = 122122
// Output: [427,286]

// Constraints:
//     1 <= area <= 10^7

import "fmt"
import "math"

func constructRectangle(area int) []int {
    r := int(math.Sqrt(float64(area)))
    for r > 1 {
        if area % r  == 0 { // 没有余数(能被整除) 最坏的情况 r = 1
            return []int{ area / r, r }
        }
        r--
    }
    return []int{area, 1}
}

func main() {
    // Example 1:
    // 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.
    fmt.Println(constructRectangle(4)) // [2,2]
    // Example 2:
    // Input: area = 37
    // Output: [37,1]
    fmt.Println(constructRectangle(37)) // [37,1]
    // Example 3:
    // Input: area = 122122
    // Output: [427,286]
    fmt.Println(constructRectangle(122122)) // [427,286]
}