[LeetCode] 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

解题思路：

顺序查找非常简单，这里尝试二分。

class Solution {
public:
int searchInsert(int A[], int n, int target) {
// IMPORTANT: Please reset any member data you declared, as
// the same Solution instance will be reused for each test case.
int left = 0, right = n - 1, mid = 0;
if(target < A[left]) return 0;
if(target > A[right]) return n;
while(true)
{
if(target == A[left]) return left;
if(target == A[right]) return right;
if(right == left + 1) return right;

mid = (left + right) / 2;
if(target == A[mid]) return mid;
else if(target < A[mid]) right = mid;
else left = mid;
}
}
};