704. Binary Search
Problem
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.
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 nums are unique.
- nums is sorted in ascending order.
Solution
pub fn search(nums: Vec<i32>,target: i32) -> i32{
let mut left=0;
let mut right=nums.len()-1;
while left<right{
let med = (left+right)/2;
if nums[med]==target{
return med as i32;
}
else if nums[med]<target{
left=med+1;
}else{
right=med-1;
}
}
return -1;
}