归并算法之有序数组合并算法实现

public class MergeOrderedArray { 
 public static int[] merge(int [] a,int []b){ 
  if(!isOrderedArray(a)){ 
   System.out.println(" array a is not an ordered array."); 
   return null; 
  } 
    
  if(!isOrderedArray(b)){ 
   System.out.println(" array b is not an ordered array."); 
   return null; 
  } 
   
  int a_len = a.length; 
  int b_len = b.length; 
  int[] merge = new int[a_len+b_len]; 
  int i=0,j=0,k=0; 
  while(i<a_len&&j<b_len){ 
   if(a[i]<b[j]){ 
    merge[k++]=a[i++]; 
   }else{ 
    merge[k++]=b[j++]; 
   } 
  } 
   
  //A数组全部合并完毕，将b数组剩余直接加入合并数组 
  if(i==a_len){ 
   for(;j<b_len;j++){ 
    merge[k++]= b[j]; 
   } 
  }else{ 
   for(;i<a_len;i++){ 
    merge[k++]= a[i]; 
   } 
  } 
   
  return merge; 
   
 } 
 
 public static boolean isOrderedArray(int [] array){ 
  if(array==null||array.length==0){ 
   return false; 
  } 
   
  for(int i = 0;i<array.length-1;i++){ 
   if(array[i]>array[i+1]){ 
    return false; 
   } 
  } 
  return true; 
 } 
  
 public static void main(String[] args) { 
  int a [] = {1,2,3,4,5}; 
  int b [] = {2,3,4,5,6,7,8,9}; 
  int [] merge = merge(a,b); 
  System.out.println(Arrays.toString(merge)); 
 } 
}