LeetCode OJ - 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

分析：二分查找，注意边界

方法一：开区间[0, n)

class Solution {public:    int searchInsert(int A[], int n, int target) {        int start = 0, end = n;        while(start < end) {            int mid = (start + end) / 2;            if(A[mid] == target) {                return mid;            } else if(A[mid] < target) {                start = mid + 1;               } else if(A[mid] > target) {                end = mid;            }        }                return start;    }};

方法二：闭区间[0, n-1]

class Solution {public:    int searchInsert(int A[], int n, int target) {        int start = 0, end = n - 1;        while(start <= end) {            int mid = (start + end) / 2;            if(A[mid] == target) {                return mid;            } else if(A[mid] < target) {                start = mid + 1;               } else if(A[mid] > target) {                end = mid - 1;            }        }                return start;    }};