Find the last position of a target number in a sorted array. Return -1 if target does not exist.

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Yes

Example

Given[1, 2, 2, 4, 5, 5].

For target =2, return 2.

For target =5, return 5.

For target =6, return -1.

class Solution {
public:
    /**
     * @param A an integer array sorted in ascending order
     * @param target an integer
     * @return an integer
     */
    int lastPosition(vector<int>& A, int target) {
        // Write your code here
        if (A.empty()) {
            return -1;
        }
        int start = 0, end = A.size() - 1;
        while (start + 1 < end) {
            int mid = start + (end - start >> 1);
            if (A[mid] > target) {
                end = mid;
            } else {
                start = mid;
            }
        }
        if (A[end] == target) {
            return end;
        } else if(A[start] == target) {
            return start;
        } else {
            return -1;
        }
    }
};