Binary Search
Difficulty: EasyTopic: ArrayBinary SearchLeetcode:792.Binary SearchGiven 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.
You must write an algorithm with O(log n) runtime complexity.
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 <= 104-104 < nums[i], target < 104- All the integers in
numsare unique. numsis sorted in ascending order.
Solution
write solution in here
/**
* @param {number[]} nums
* @param {number} target
* @return {number}
*/
var search = function(nums, target) {
let l = 0, r = nums.length - 1
while(l <= r) {
let mid = Math.floor((l + r) / 2)
if (nums[mid] === target) {
return mid
}
if (nums[mid] > target) {
r --
} else {
l ++
}
}
return -1
};