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 < 104nums are unique.nums is sorted in ascending order.class Solution {
public:
int search(vector<int>& nums, int target) {
int lt=0, rt=nums.size()-1, mid;
while(lt<rt){
mid=lt+(rt-lt)/2;
nums[mid]<target?lt=mid+1:rt=mid;
}
return nums[lt]==target?lt:-1;
}
};class Solution {
public int search(int[] nums, int target) {
int lt = 0, rt = nums.length - 1;
while (lt <= rt) {
int mid = (lt + rt) / 2;
if (nums[mid] == target)
return mid;
else if (nums[mid] < target) {
lt = mid + 1;
} else {
rt = mid - 1;
}
}
return -1;
}
}