leetcode 二分查找

704. Binary Search

代码：

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int n = nums.size();
        int left = 0;
        int right = n-1;
        int res = -1;
        while(left <= right){
            int mid = (left+right)/2;
            if(nums[mid] == target){
                res = mid;
                break;
            }
            else if(nums[mid] > target){
                right = mid -1;
            }
            else{
                left = mid + 1;
            }
        }
        return res;
    }
};

35. Search Insert Position

代码：

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        int n = nums.size();
        int left = 0;
        int right = n-1;
        int res = 0;
        int mid = 0;
        while(left <= right){
            mid = (left + right)/2;
            if(nums[mid] == target){
                res = mid;
                break;
            }else if(nums[mid] > target){
                right = mid -1;
            }else{
                left = mid +1;
            }
        }
        if(left >right)
            res = left;
        return res;
    }
};