35. Search Insert Position

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

You may assume no duplicates in the array.

Here are few examples.
[1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0

经典二分搜索
想想为什么返回l，可以把找不到目标的可能性分情况讨论一下

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        int l = 0;
        int r = nums.size() - 1;

        while (l <= r) {
            int mid = (l + r) / 2;
            if (nums[mid] == target) return mid;

            if (nums[mid] < target) l = mid + 1;
            if (nums[mid] > target) r = mid - 1;
        }

        return l;
    }
};