leetcode剑指offer53–n-1中缺失的数字（二分//or等差数列）

int missingNumber(int* nums, int numsSize){
    int mid;
    int low = 0;
    int high = numsSize-1;
    if(nums[low] == 1)
        return low;
    if(nums[high] == high)
        return high+1;
    while(low < high) //low 不能与 high相等
    {
        mid = (low+high)/2;
        // printf("%d",mid);
        if(nums[mid] != mid)
        {
            //dangqianyijingjingliqueshi
            high = mid;
        }
        else
        {
            low = mid+1;
        }
    }
    return low;
}