题目描述

Given two sorted integer arrays A and B, merge B into A as one sorted array.

Note:

You may assume that A has enough space (size that is greater or equal to m + n) to hold additional elements from B. The number of elements initialized in A and B are m and n respectively.

解题思路：

class Solution:

    # @param A  a list of integers

    # @param m  an integer, length of A

    # @param B  a list of integers

    # @param n  an integer, length of B

    # @return nothing(void)

    def merge(self, A, m, B, n):

        posa = m - 1

        posb = n - 1

        for i in range(m+n-1,-1,-1):

            if posa < 0:

                A[i] = B[posb]

                posb -= 1

            elif posb < 0:

                return

            elif A[posa] > B[posb]:

                A[i] = A[posa]

                posa -= 1

            else:

                A[i] = B[posb]

                posb -= 1