题解 | #二分查找-I#

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param nums int整型vector 
     * @param target int整型 
     * @return int整型
     */
    int search(vector<int>& nums, int target) {
        // write code here
        int pos = nums.size()-1;
        int start=0,end=nums.size()-1;
        while ((end-start)>1 && nums.size()>2) {
            pos = (int)(start+end)/2;
            if (nums[pos]<target) {
                start=pos;
            }else if(nums[pos]>target){
                end=pos;
            }else{
                return pos;
            }
        }
        if (end - start == 1 || nums.size()==1) {
            return target==nums[start]?start:(target==nums[end]?end:-1);
        }


        return -1;
    }
};