【Java】LeetCode题答-704二分查找

2021-06-30 | 算法与数据结构 | | | 185

LeetCood题目

题答1（递归解法完整代码）

//704
class Solution {
    public int search(int[] nums, int target) {

        return search(nums ,0, nums.length-1, target);
    }

    private int search(int[] data, int l , int r, int target){

        if(l > r) return -1;

        int mid = l + (r - l) / 2;
        if(data[mid] == target)
            return mid;
        if(data[mid] < target )
            return search(data, mid + 1, r, target);
        else
            return search(data, l, mid - 1 , target);
    }
}

题答2（非递归解法完整代码）

//704
class Solution {

    public  int search(int[] nums, int target){

        int l = 0, r = nums.length - 1;

        // 在data[l, r ]范围中查找 target
        while(l <= r){
            int mid = l + (r - l ) / 2;
            if(nums[][mid] == target)
                return mid;
            if(nums[mid] < target)
                l = mid + 1;
            else
                r = mid - 1;
        }
        return -1;
    }
}