Search Insert Position @leetcode

#二分我好乱

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.
        if(n == 0) return n;
        if(target < A[0]) return 0;
        else if(target > A[n-1]) return n;
        else if(n == 2)
        {
            if(target == A[0]) return 0;
            if(target <= A[1]) return 1;
        }
        int b,e;
        b=0;e=n-1;
        while(b+1<e)
        {
            if(A[b] == target) return b;
            if(A[e] == target) return e;
            if(A[(e+b)/2]>target)
                e=(e+b)/2;
            else if(A[(e+b)/2]<target)
                b=(e+b)/2;
            else
                return (e+b)/2;
        }
        return e;
    }
};

#nb版

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;
        int mid = 0;
        while (left < right) {
            mid = left + (right - left) / 2;
            if (A[mid] > target) {
                right = mid;
            } else if (A[mid] < target) {
                left = mid + 1;
            } else {
                return mid;
            }
        }
        return left;
    }
};