import java.util.ArrayList; import java.util.HashSet; import java.util.Iterator; import java.util.Set; public class Test { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub ArrayList<Integer> list1 = new ArrayList<Integer>(); for(int i = 0 ; i < 5; i ++){ list1.add(i); } list1.add(4); ArrayList<Integer> list2 = new ArrayList<Integer>(); for(int i = 0 ; i < 10; i ++){ list2.add(i); } deleteRepeatData(list1); deleteRepeatData(list2); intersect(list1, list2); Integer integer[] = union(list1, list2); for(int i = 0 ; i < integer.length ; i ++){ System.out.println("union(list1, list2);== "+ integer[i]); } } /** * 数组的交集 * @param list1 * @param list2 */ private static void intersect(ArrayList<Integer> list1, ArrayList<Integer> list2) { int size1 = list1.size(); int size2 = list2.size(); if(size1 > size2){ for(int i = 0 ; i < size1 ; i ++){ for(int k = 0 ; k < size2 ; k ++){ if(list1.get(i) == list2.get(k)){ System.out.println("list1.get("+ i + ") == " + list1.get(i)); } } } }else{ for(int i = 0 ; i < size2 ; i ++){ for(int k = 0 ; k < size1 ; k ++){ if(list2.get(i) == list1.get(k)){ System.out.println("list2.get("+ i + ") == " + list2.get(i)); } } } } } /** *去掉数组中重复的数据 * @param numList */ private static void deleteRepeatData(ArrayList<Integer> numList) { Iterator<Integer> iterator = numList.iterator(); int temp = -1; if(iterator.hasNext()){ temp = iterator.next(); } while(iterator.hasNext()){ int i = iterator.next(); if(i == temp ){ iterator.remove(); }else{ temp = i; } } System.out.println(numList); } /** * 数组的并集 * 求两个字符串数组的并集,利用set的元素唯一性 * @param arrayList1 * @param arrayList2 * @return */ public static Integer[] union(ArrayList<Integer> arrayList1,ArrayList<Integer> arrayList2){ Set<Integer> set = new HashSet<Integer>(); for(Integer in : arrayList1){ set.add(in); } for(Integer in : arrayList2){ set.add(in); } Integer[] integers = new Integer[]{}; set.toArray(integers); return set.toArray(integers); } }
java 实现数组的交集和并集
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转载自1002878825-qq-com.iteye.com/blog/1633754
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