class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        if (nums.empty()) return 0;
        int l = 0, r = nums.size() - 1;
        if (target > nums[nums.size() - 1]) return nums.size();
        while (l < r) {
            int mid = l + r >> 1;
            if (nums[mid] >= target) r = mid;
            else l = mid + 1;
        }
        return l;
    }
};

yxc代码：

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        int l = 0, r = nums.size(); //因为 l+r >> 1是下取整，所以不会越界 mid不会取到nums.size()
        while (l < r) {
            int mid = l + r >> 1;
            if (nums[mid] >= target) r = mid;
            else l = mid + 1;
        }
        return l;
    }
};