[leetcode]-704. Binary Search（C语言）

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:

1. You may assume that all elements in nums are unique.
2. n will be in the range [1, 10000].
3. The value of each element in nums will be in the range [-9999, 9999].

int search(int* nums, int numsSize, int target) {
    int low=0;
    int high=numsSize-1;
    int mid=(high+low)/2;
    while(low<=high)
    {
        if(nums[mid]==target)
            return mid;
        else if(nums[mid]>target)
            high=mid-1;
        else
            low=mid+1;
        mid=(low+high)/2;
    }
    return -1;
}