Search_Insert_Position.cpp

/*
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.

Example
[1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0
*/
#include <vector>

using namespace std;

class Solution {
    /**
     * param A : an integer sorted array
     * param target :  an integer to be inserted
     * return : an integer
     */
  public:
    int searchInsert(vector<int>& A, int target) {
        // write your code here
        if (A.empty()) {
            return 0;
        }
        if (target <= A[0]) {
            return 0;
        }
        if (target > A.back()) {
            return A.size();
        }
        int start = 0, end = A.size() - 1;
        while (start <= end)  {
            int mid = start + (end - start) / 2; // overflow
            if (A[mid] == target) {
                return mid;
            }
            if (mid > start && A[mid] > target && A[mid - 1] < target) {
                return mid;
            }
            if (A[mid] > target) {
                end = mid - 1;
            } else {
                start = mid + 1;
            }
        }
        return start;
    }
};