Merge Sorted Array (Java)

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.

倒着插入，因为正着插入可能会导致A中的数据移动，倒着不会

Source

    public void merge(int A[], int m, int B[], int n) {
        int a = m - 1, b = n - 1, c = m + n - 1;
        
        while( a >= 0 && b >= 0){
        	if(A[a] > B[b]){
        		A[c] = A[a];
        		c --;
        		a --;
        	}
        	else{
        		A[c] = B[b];
        		c --;
        		b --;
        	}
        }
        while(a >= 0){
        	A[c] = A[a];
        	c --;
        	a --;
        }
        while(b >= 0){
        	A[c] = B[b];
        	c --;
        	b --;
        }
     
        	//System.out.println(Arrays.toString(A));
    }

Test

public static void main(String[] args){
    	int[] A = {1,2,3,4,5,0,0};   //A数组开大一点，如果只开m的大小肯定会越界
    	int[] B = {4,6};
     	
    	new Solution().merge(A,5,B,2);  //传的时候没必要传开的那么大
    }