🌗 704. 二分查找

难度: 🌗

• 问题描述
• 解法
• 输出

问题描述

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解法

class Solution {
    public int search(int[] nums, int target) {
        // 思路：
        // 二分
        int len = nums.length;
        return mySol(nums, target, 0, len - 1);
    }

    private int mySol(int[] nums, int target, int left, int right) {
        // 递归终止条件
        if(left > right) {
            return -1;
        }
        if(left == right) {
            if(nums[left] == target) {
                return left;
            } else {
                return -1;
            }
        }
        // left < right
        int mid = left + ((right - left) >> 1);
        if(nums[mid] == target) {
            return mid;
        } else if(target > nums[mid]) {
            left = mid + 1;
            return mySol(nums, target, left, right);
        } else {
            right = mid - 1;
            return mySol(nums, target, left, right);
        }
    }
}

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输出