LeetCode 492. Construct the Rectangle （算法）

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.

輸入一個正整數n，將其拆成兩個正整數L和W的乘積，使L和W的差最小，且L>=W。

思路：從根號n開始遍歷，直到找到第一個能夠整除n的數。

    vector<int> constructRectangle(int area) {
        int s = sqrt(area),l;
        for (l=s;l<=area;l++)
        {
            if(area%l==0)
                break;
        }
        vector<int> ans(0);
        ans.push_back(l);
        ans.push_back(area/l);
        sort(ans.begin(),ans.end(),greater<int>());
        return ans;
    }