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Commit 5655451

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Custom HashSet done
1 parent 08d0d61 commit 5655451

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3 files changed

+144
-1
lines changed

3 files changed

+144
-1
lines changed

‎src/main/java/com/leetcode/arrays/RemoveDuplicates.java

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -15,14 +15,16 @@
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* <p>
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* Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively.
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* <p>
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* It doesn't matter what you leave beyond the returned length.
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* NOTE: It doesn't matter what you leave beyond the returned length.
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*
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* @author rampatra
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* @since 2019年04月24日
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*/
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public class RemoveDuplicates {
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/**
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* This removes the duplicates from the array in-place.
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* <p>
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* Time complexity: O(n)
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* where,
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* n = no. of elements in the array
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package com.leetcode.hashtables;
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import java.util.Arrays;
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import java.util.HashSet;
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import java.util.Set;
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/**
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* Level: Easy
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* Problem Link: https://leetcode.com/problems/contains-duplicate/
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*
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* @author rampatra
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* @since 2019年04月24日
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*/
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public class ContainsDuplicates {
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public static boolean containsDuplicates(int[] nums) {
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Set<Integer> numSet = new HashSet<>();
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for (int num : nums) {
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if (!numSet.add(num)) {
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return true;
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}
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}
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return false;
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}
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/**
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* Runtime: <a href="https://leetcode.com/submissions/detail/224724092/">5 ms</a>.
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*
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* @param nums
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* @return
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*/
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public static boolean containsDuplicatesWithoutSet(int[] nums) {
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Arrays.sort(nums);
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for (int i = 0; i < nums.length - 1; i++) {
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if (nums[i] == nums[i + 1]) {
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return true;
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}
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}
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return false;
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}
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public static void main(String[] args) {
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System.out.println(containsDuplicates(new int[]{1, 2, 3, 1}));
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System.out.println(containsDuplicates(new int[]{1, 2, 3, 4}));
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System.out.println(containsDuplicatesWithoutSet(new int[]{1, 2, 3, 1}));
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System.out.println(containsDuplicatesWithoutSet(new int[]{1, 2, 3, 4}));
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}
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}
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package com.leetcode.hashtables;
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/**
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* Level: Learning Cards
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* Problem Link: https://leetcode.com/explore/learn/card/hash-table/182/practical-applications/1139/
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*
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* @author rampatra
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* @since 2019年04月24日
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*/
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public class MyHashSet {
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private final int SIZE = 10000;
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private final Entry[] entries;
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class Entry {
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int key;
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Entry next;
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Entry(int key) {
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this.key = key;
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}
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}
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/**
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* Initialize your data structure here.
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*/
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public MyHashSet() {
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entries = new Entry[SIZE];
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}
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public void add(int key) {
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if (contains(key)) return;
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Entry newEntry = new Entry(key);
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int bucket = key % SIZE;
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newEntry.next = entries[bucket];
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entries[bucket] = newEntry;
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}
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public void remove(int key) {
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int bucket = key % SIZE;
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Entry entry = entries[bucket];
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if (entry != null && entry.key == key) {
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entries[bucket] = entry.next;
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return;
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}
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Entry curr = new Entry(0);
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curr.next = entry;
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while (curr.next != null && curr.next.key != key) {
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curr = curr.next;
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}
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if (curr.next != null) {
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curr.next = curr.next.next;
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}
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}
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/**
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* Returns true if this set contains the specified element
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*/
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public boolean contains(int key) {
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int bucket = key % SIZE;
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Entry entry = entries[bucket];
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while (entry != null) {
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if (entry.key == key) {
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return true;
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}
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entry = entry.next;
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}
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return false;
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}
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public static void main(String[] args) {
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MyHashSet set = new MyHashSet();
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set.add(1);
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set.add(2);
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set.add(3);
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System.out.println(set.contains(1));
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System.out.println(set.contains(2));
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set.remove(2);
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System.out.println(set.contains(2));
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System.out.println(set.contains(3));
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set.remove(3);
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System.out.println(set.contains(3));
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}
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}

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