Sqrt(x)

最新推荐文章于 2021-07-27 17:36:18 发布

xiaoxiaoluo

最新推荐文章于 2021-07-27 17:36:18 发布

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转自：http://blog.youkuaiyun.com/linhuanmars/article/details/20089131

class Solution {
public:
    int sqrt(int x) {
          if(x < 0) {
            return -1;
        }
        if(x == 0) {
            return 0;
        }
        int low = 1, high = x / 2 + 1;
        while(low <= high) {
            int mid = (low + high) / 2;
            if(mid <= x / mid && (mid + 1) > x / (mid + 1)) {
                return mid;
            }
            if(mid < x / mid) {
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        return 0;
    }
};

牛顿迭代法：

const double epsilon = 1e-5;
class Solution {
public:
    int sqrt(int x) {
          if(x < 0) {
            return -1;
        }
        if(x == 0) {
            return 0;
        }
        double last = 0;
        double result = 1;
        while(abs(result - last) > epsilon) {
            last = result;
            result = (result + x / result) / 2.0;
        }
        return result;
    }
};