leetcode practice problem solutions

.idea/.gitignore

+# Default ignored files
+/shelf/
+/workspace.xml

.idea/compiler.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="leetcode" />
+      </profile>
+    </annotationProcessing>
+  </component>
+</project>
\ No newline at end of file

.idea/jarRepositories.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://repo.maven.apache.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+  </component>
+</project>
\ No newline at end of file

.idea/misc.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="corretto-1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
\ No newline at end of file

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>leetcode</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
+    </properties>
+
+</project>
\ No newline at end of file

src/main/java/ArrayIntersection.java

+import java.util.*;
+
+// LeetCode: 2248
+public class ArrayIntersection {
+    public List<Integer> solution(int[][] nums) {
+        List<Integer> result = new ArrayList<>();
+        int lengthOfNums = nums.length;
+        Map<Integer, Integer> myMap = new HashMap<>();
+        for (int i = 0; i < lengthOfNums; i++) {
+            for (int j = 0; j < nums[i].length; j++) {
+                if(!myMap.containsKey(nums[i][j])){
+                    myMap.put(nums[i][j], 1);
+                }
+                else {
+                    myMap.put(nums[i][j], myMap.get(nums[i][j])+1);
+                }
+            }
+        }
+        for(int key: myMap.keySet()) {
+            int mapKeyValue = myMap.get(key);
+            if (mapKeyValue == lengthOfNums) {
+                result.add(key);
+            }
+        }
+        result.sort(Comparator.naturalOrder());
+        return result;
+    }
+    public static void main(String[] args) {
+        int[][] nums = {{7,34,45,10,12,27,13},{27,21,45,10,12,13}};
+        System.out.println(nums[1].length);
+        ArrayIntersection myArray = new ArrayIntersection();
+        System.out.println(myArray.solution(nums));
+    }
+}

src/main/java/ClosestToZero.java

+// LeetCode: 2239
+public class ClosestToZero {
+
+    public int solution(int[] nums) {
+        int min = Integer.MAX_VALUE;
+        int number = 0;
+        for(int x: nums) {
+            if(x == 0) {
+                return 0;
+            }
+            else if (Math.abs(x) < Math.abs(min)){ // min = -4, x = 1
+                min = x;
+            }
+            else if(Math.abs(x) == Math.abs(min)) {
+                min = Math.max(x, min);
+            }
+
+        }
+        return min;
+    }
+
+    public static void main(String[] args) {
+        int[] nums = {-4,-2,2,4,8};
+        ClosestToZero zero = new ClosestToZero();
+        System.out.println(zero.solution(nums));
+    }
+}

src/main/java/MaxPairs.java

+import java.util.HashMap;
+import java.util.Map;
+
+//LeetCode 2341
+public class MaxPairs {
+    public int[] solution(int[] nums) {
+        int remainder =  0;
+        int pairs = 0;
+        Map<Integer, Integer> myMap = new HashMap<>();
+        for(int x: nums) {
+            if (myMap.get(x) == null) {
+                myMap.put(x,1);
+            }
+            else{
+                int currentValue = myMap.get(x);
+                myMap.put(x, currentValue + 1);
+            }
+        }
+        for(int key: myMap.keySet()) {
+            int p = (int) myMap.get(key) / 2;
+            int r = myMap.get(key) % 2;
+            remainder += r;
+            pairs += p;
+        }
+        int[] ans = {pairs, remainder};
+        return ans;
+    }
+    public static void main(String[] args) {
+        MaxPairs maxPairs = new MaxPairs();
+        int[] arr = {1,3,2,1,3,2,2};
+        int[] ans = maxPairs.solution(arr);
+        System.out.println(maxPairs.solution(arr));
+
+    }
+}

src/main/java/ZeroArray.java

+// LeetCode: 2357
+public class ZeroArray {
+    public int sums(int[] nums) {
+        int sum = 0;
+        for(int x: nums) {
+            sum = sum + x;
+        }
+        return sum;
+    }
+    public int findMin(int[] nums) {
+        int min = Integer.MAX_VALUE;
+        for(int x: nums) {
+            if (x < min && x != 0) {
+                min = x;
+            }
+        }
+        return min;
+    }
+    public int solution(int[] nums) {
+        int count = 0;
+        int sum = sums(nums);
+        while(sum > 0) {
+            int min = findMin(nums);
+            for (int i = 0; i < nums.length; i++) {
+                if(nums[i] != 0) {
+                    nums[i] = nums[i] - min;
+                }
+            }
+            sum = sums(nums);
+            count ++;
+        }
+        return count;
+    }
+    public static void main(String[] args) {
+        ZeroArray zero = new ZeroArray();
+        int[] myNums = {1,5,0,3,5};
+        System.out.println(zero.solution(myNums));
+    }
+
+}