[lintcode easy]Merge Sorted Array

Merge Sorted Array

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

 

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Example

A = [1, 2, 3, empty, empty], B = [4, 5]

After merge, A will be filled as [1, 2, 3, 4, 5]

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.

 

///Because it is sorted array, we can compare them from the end to the start.

///which one is greater, put it in the last array A

///keep decreasing m and n

///until m or n equal to 0

///if m=0, copy all the numbers in array B to A;

class Solution {
    /**
     * @param A: sorted integer array A which has m elements, 
     *           but size of A is m+n
     * @param B: sorted integer array B which has n elements
     * @return: void
     */
    public void mergeSortedArray(int[] A, int m, int[] B, int n) {
        // write your code here
        while(m>0&&n>0)
        {
           if(A[m-1]>B[n-1])
           {
               A[m+n-1]=A[m-1];
               m--;
           }
           else
           {
               A[m+n-1]=B[n-1];
               n--;
           }
        }
        
        while(n>0)
        {
            A[m+n-1]=B[n-1];
            n--;
        }
        
    }
}