README_EN.md

704. Binary Search

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Description

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1.

 

Example 1:

Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4
Explanation: 9 exists in nums and its index is 4

Example 2:

Input: nums = [-1,0,3,5,9,12], target = 2
Output: -1
Explanation: 2 does not exist in nums so return -1

 

Constraints:

• 1 <= nums.length <= 104
• -9999 <= nums[i], target <= 9999
• All the integers in nums are unique.
• nums is sorted in an ascending order.

Solutions

Python3

class Solution:
    def search(self, nums: List[int], target: int) -> int:
        low, high = 0, len(nums) - 1
        while low <= high:
            mid = (low + high) >> 1
            if nums[mid] == target:
                return mid
            if nums[mid] < target:
                low = mid + 1
            else:
                high = mid - 1
        return -1

Java

class Solution {
    public int search(int[] nums, int target) {
        int low = 0, high = nums.length - 1;
        while (low <= high) {
            int mid = (low + high) >>> 1;
            if (nums[mid] == target) {
                return mid;
            }
            if (nums[mid] < target) {
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        return -1;
    }
}

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