二分算法-LeetCode 69

int binarySearch(int[] nums, int target) {
    int left = 0; 
    int right = nums.length - 1; // 注意

    while(left <= right) { // 注意
        int mid = (right + left) / 2;
        if(nums[mid] == target)
            return mid; 
        else if (nums[mid] < target)
            left = mid + 1; // 注意
        else if (nums[mid] > target)
            right = mid - 1; // 注意
        }
    return -1;
}

public class LeetCode69 {
    // 二分算法
    int mySqrt(int x) {
        int l = 1;
        int h = x;
        while (l <= h) {
            int mid = l + (h - l) / 2;
            int sqrt = x / mid;
            if (sqrt == mid) {
                return mid;
            } else if (sqrt < mid) {
                h = mid - 1;
            } else {
                l = mid + 1;
            }
        }
        return h;
    }

    public static void main(String[] args) {
        System.out.println(new LeetCode69().mySqrt(8));
    }
}