feat: add 217. Contains Duplicate

Author: nphausg

.gitignore

@@ -18,8 +18,6 @@
 *.zip
 *.tar.gz
 *.rar
-
+*.DS_Store
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*
-src/.DS_Store
-src/com/nphausg/.DS_Store

README.md

@@ -28,19 +28,20 @@ Medium: https://medium.com/@nphausg
 
 ## 💎 Coding Challenges
 
-| Challenge                                                                                                          | Level  | Java                                                                        | Kotlin                                                            |
-|--------------------------------------------------------------------------------------------------------------------|--------|-----------------------------------------------------------------------------|-------------------------------------------------------------------|
-| [0001. Two sum](https://leetcode.com/problems/two-sum)                                                             | 🔥     | -                                                                           | [Solution](src/com/nphausg/leetcode/easy/TwoSum.kt)      |
-| [0020. ValidParentheses](https://leetcode.com/problems/valid-parentheses)                                          | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ValidParentheses.java)             | -                                                                 |
-| [0026. Remove Duplicates](https://leetcode.com/problems/remove-duplicates-from-sorted-array)                       | 🔥     | [Solution](src/com/nphausg/leetcode/easy/RemoveDuplicates.java)             | -                                                                 |
-| [0027. Remove Element](https://leetcode.com/problems/remove-element)                                               | 🔥     | [Solution](src/com/nphausg/leetcode/easy/RemoveElement.java)                | -                                                                 |
-| [0121. Best time to buy and sell stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock)             | 🔥     | -                                                                           | [Solution](src/com/nphausg/leetcode/easy/BuyAndSellStock.kt)      |
-| [1929. Concatenation Of Array](https://leetcode.com/problems/concatenation-of-array)                               | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ConcatenationArray.java)           | -                                                                 |
-| [0017. Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number) | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/LetterCombinations.java)         | -                                                                 |
-| [0091. Decode Ways ](https://leetcode.com/problems/decode-ways)                                                    | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/DecodeWays.java)                 | -                                                                 |
-| [1143. Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence)                       | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/LongestCommonSubsequence.java)   |
-| [0658. Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements)                             | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/FindClosestElements.java)        | -                                                                 |
-| [0041. First Missing Positive](https://leetcode.com/problems/first-missing-positive)                               | 🔥🔥🔥 | [Solution](src/com/nphausg/leetcode/hard/FirstMissingPositive.java)         | [Solution](src/com/nphausg/leetcode/hard/FirstMissingPositive.kt) |
+| Challenge                                                                                                          | Level  | Java                                                                      | Kotlin                                                            |
+|--------------------------------------------------------------------------------------------------------------------|--------|---------------------------------------------------------------------------|-------------------------------------------------------------------|
+| [0001. Two sum](https://leetcode.com/problems/two-sum)                                                             | 🔥     | -                                                                         | [Solution](src/com/nphausg/leetcode/easy/TwoSum.kt)               |
+| [0020. ValidParentheses](https://leetcode.com/problems/valid-parentheses)                                          | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ValidParentheses.java)           | -                                                                 |
+| [0026. Remove Duplicates](https://leetcode.com/problems/remove-duplicates-from-sorted-array)                       | 🔥     | [Solution](src/com/nphausg/leetcode/easy/RemoveDuplicates.java)           | -                                                                 |
+| [0027. Remove Element](https://leetcode.com/problems/remove-element)                                               | 🔥     | [Solution](src/com/nphausg/leetcode/easy/RemoveElement.java)              | -                                                                 |
+| [0121. Best time to buy and sell stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock)             | 🔥     | -                                                                         | [Solution](src/com/nphausg/leetcode/easy/BuyAndSellStock.kt)      |
+| [0217. Contains Duplicate](https://leetcode.com/problems/contains-duplicate)                                       | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ContainsDuplicate.java)          | -                                                                 |
+| [1929. Concatenation Of Array](https://leetcode.com/problems/concatenation-of-array)                               | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ConcatenationArray.java)         | -                                                                 |
+| [0017. Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number) | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/LetterCombinations.java)       | -                                                                 |
+| [0091. Decode Ways ](https://leetcode.com/problems/decode-ways)                                                    | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/DecodeWays.java)               | -                                                                 |
+| [1143. Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence)                       | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/LongestCommonSubsequence.java) |
+| [0658. Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements)                             | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/FindClosestElements.java)      | -                                                                 |
+| [0041. First Missing Positive](https://leetcode.com/problems/first-missing-positive)                               | 🔥🔥🔥 | [Solution](src/com/nphausg/leetcode/hard/FirstMissingPositive.java)       | [Solution](src/com/nphausg/leetcode/hard/FirstMissingPositive.kt) |
 
 ![-----------------------------------------------------](https://raw.githubusercontent.com/andreasbm/readme/master/assets/lines/colored.png)
 

src/com/nphausg/leetcode/.DS_Store

@@ -0,0 +1,43 @@
+package com.nphausg.leetcode.easy;
+
+import java.util.Arrays;
+import java.util.HashSet;
+
+/**
+ * <a href="https://leetcode.com/problems/contains-duplicate">Contains duplicate</a>
+ */
+public class ContainsDuplicate {
+    public boolean containsDuplicate(int[] nums) {
+        for (int i = 0; i < nums.length - 1; i++) {
+            for (int j = i + 1; j < nums.length; j++) {
+                if (nums[j] == nums[i]) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    public boolean containsDuplicate2(int[] nums) {
+        Arrays.sort(nums);
+        for (int i = 1; i < nums.length; i++) {
+            if (nums[i] == nums[i - 1]) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public boolean containsDuplicate3(int[] nums) {
+        HashSet<Integer> set = new HashSet<>();
+        for (int i = 1; i < nums.length; i++) {
+            if (set.contains(nums[i])) {
+                return true;
+            }
+            set.add(nums[i]);
+        }
+        return false;
+    }
+
+
+}