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Change filename for Intersection.java file (#3178)

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Co-authored-by: Yang Libin <contact@yanglibin.info>
This commit is contained in:
Susobhan Das
2022-07-05 15:20:46 +05:30
committed by GitHub
parent 3fb9a606a3
commit f7c40ad749
2 changed files with 38 additions and 64 deletions
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64
src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection
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@ -1,64 +0,0 @@
package com.thealgorithms.datastructures.hashmap.hashing;
/*
* this is algo which implies common mathematical set theory concept
* called intersection in which result is common values of both the sets
* here metaphor of sets is HashMap
Test Case:
Scanner scn=new Scanner(System.in);
int len =scn.nextInt();
int arr[]=new int[len];
int arr2[]=new int[len];
for(int i=0;i<2*len;i++) {
if(i<len)
arr[i]=scn.nextInt();
if(i>=len) {
arr2[i-len]=scn.nextInt();
}
}
System.out.println(Main(arr,arr2));
*/
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
public class Intersection {
public static ArrayList Main(int arr[],int arr2[]) {
HashMap<Integer,Integer> hmap=new HashMap<>();
HashMap<Integer,Integer> hmap2=new HashMap<>();
for(int i=0;i<arr.length;i++) {
if(hmap.containsKey(arr[i])) {
int val=hmap.get(arr[i]);
hmap.put(arr[i],val+1);
}else
hmap.put(arr[i],1);
}
ArrayList<Integer> res=new ArrayList<>();
for(int i=0;i<arr2.length;i++) {
if(hmap.containsKey(arr2[i])&&hmap.get(arr2[i])>0) {
int val=hmap.get(arr2[i]);
hmap.put(arr2[i],val-1);
res.add(arr2[i]);
}
}
return res;
}
public Intersection() {
}
}

38
src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java Normal file
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@ -0,0 +1,38 @@
package com.thealgorithms.datastructures.hashmap.hashing;
/*
* this is algo which implies common mathematical set theory concept
* called intersection in which result is common values of both the sets
* here metaphor of sets is HashMap
*/
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class Intersection {
public static List<Integer> intersection(int[] arr1, int[] arr2) {
if (arr1 == null || arr2 == null || arr1.length == 0 || arr2.length == 0) {
return Collections.emptyList();
}
Map<Integer, Integer> cnt = new HashMap<>(16);
for (int v : arr1) {
cnt.put(v, cnt.getOrDefault(v, 0) + 1);
}
List<Integer> res = new ArrayList<>();
for (int v : arr2) {
if (cnt.containsKey(v) && cnt.get(v) > 0) {
res.add(v);
cnt.put(v, cnt.get(v) - 1);
}
}
return res;
}
private Intersection() {
}
}