492. Construct the Rectangle -E

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.

A:

---------------------瞧瞧自己有多傻------- 从sqrt开始，按照 L 和 W的距离越来越大 ，逐次寻找 .  就只第一次用了sqrt()   其实可以不用的 -------------------

class Solution {
public:
    vector<int> constructRectangle(int area) {
        int W = sqrt(area);
        int dist = 0;
        vector<int> res;
        for(int dist = 0; dist < area; ++dist)
        {
            int t = W*(W+dist);
            if(t == area)
            {
                res = { W+dist, W};
                break;
            }else if(t < area){
                while(t<area){
                    ++W;
                    t = W * (W+dist);
                }
                if(t == area){
                    res = {W+dist, W};
                    break;
                }
            }else{ // current is bigger                
                while(t > area){
                    --W;
                    t = W * (W+dist);
                }
                if(t == area){
                    res = {W+dist, W};
                    break;
                }
            }
        }
        return res;
    }
};

---------------- 直接开始除------------------------TNND-------------

class Solution {
public:
    vector<int> constructRectangle(int area) {
        for(int W = sqrt(area);W>=1;--W)
        {
            if(area%W ==0)
                return {area/W, W};
        }
        return {-1,-1};
    }
};