求有序整数集合a和b的交集函数
问题描述：有两个有序整数集合a和b，写一个函数找出它们的交集？
几种解决方案：
一：
import java.util.Arrays; public class Test { public static void main(String args[]){ int[] b = {4, 6, 7, 7, 7, 7, 8, 8, 9, 10, 100, 130, 130, 140, 150}; int[] a = {2, 3, 4, 4, 4, 4, 7, 8, 8, 8, 8, 9, 100, 130, 150, 160}; int[] c = intersect(a, b); System.out.println(Arrays.toString(c)); } public static int[] intersect(int[] a, int[] b) { if(a > b || b > a) { return new int; } int[] intersection = new int; int offset = 0; for(int i = 0, s = i; i < a.length && s < b.length; i++) { while(a > b) { s++; } if(a == b) { intersection = b; } while(i < (a.length - 1) && a == a) { i++; } } if(intersection.length == offset) { return intersection; } int[] duplicate = new int; System.arraycopy(intersection, 0, duplicate, 0, offset); return duplicate; } }
import java.util.ArrayList; public class jiaoji { public static void main(String[] args) { // TODO Auto-generated method stub int[] b = { 4, 6, 7, 7, 7, 8, 8, 9, 10, 100, 130, 140, 150 }; int[] a = { 2, 3, 4, 4, 4, 7, 8, 8, 8, 8, 9, 100, 130, 150, 160 }; ArrayList c = sect(a, b); for (int i = 0; i < c.size(); i++) { System.out.print(c.get(i) + ","); } } public static ArrayList sect(int[] a, int[] b) { int k = 0; int startposb = 0; if (a > b || b > a) { return new ArrayList(); } ArrayList arraylist = new ArrayList(); for (int i = 0; i < a.length; i++) { for (int j = startposb; j < b.length; j++) { if (a == b) { arraylist.add(k, a); k++; startposb = j + 1; break; } } } return arraylist; } }
import java.util.HashSet; import java.util.Iterator; import java.util.Set; public class NumberCross { public static void main(String[] args) { int a[] = {1,3,4,5,6,7,499,199}; int b[] = {3,299,199,8,9,499}; Set<Integer> list = new HashSet<Integer>(); for(int i=0; i<a.length; i++) { list.add(a); } for(int j=0; j<b.length; j++) { list.add(b); } for(Iterator<Integer> iter=list.iterator(); iter.hasNext();) { System.out.print(iter.next() + " "); } } }
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