7. Binary Search
Oct 20, 2020
Given a sorted (in ascending order) integer array nums
of n
elements and a target
value, 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
Note:
- You may assume that all elements in
nums
are unique. n
will be in the range[1, 10000]
.- The value of each element in
nums
will be in the range[-9999, 9999]
.
Solution
class Solution {
public int search(int[] nums, int target) {
int low = 0;
int high = nums.length-1;
while(low<=high) {
int mid = (low+high)/2;
if(nums[mid] == target) {
return mid;
} else if (nums[mid] > target) {
high = mid-1;
} else {
low = mid+1;
}
}
return -1;
}
}