leetcode 刷道题 70 earch Insert Position 二进制搜索插入位置

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

二分查找。一点小的差别就是当数组不含目标数字时，返回应该插入的位置。

AC code：

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

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