Completed May 22

Author: adnanhakim

.idea/.gitignore

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/misc.xml

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+package MayChallenges;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+
+/*
+May 22
+
+Question: Sort Characters By Frequency
+Given a string, sort it in decreasing order based on the frequency of characters.
+
+https://leetcode.com/explore/challenge/card/may-leetcoding-challenge/537/week-4-may-22nd-may-28th/3337/
+*/
+
+class May22 {
+    static class Alphabet {
+        char letter;
+        int count;
+
+        Alphabet(char letter, int count) {
+            this.letter = letter;
+            this.count = count;
+        }
+    }
+
+    public String frequencySort(String s) {
+        StringBuilder builder = new StringBuilder();
+        HashMap<Character, Integer> hashMap = new HashMap<>();
+        ArrayList<Alphabet> alphabets = new ArrayList<>();
+
+        for (int i = 0; i < s.length(); i++) {
+            char letter = s.charAt(i);
+            if (hashMap.containsKey(letter)) hashMap.put(letter, hashMap.get(letter) + 1);
+            else hashMap.put(letter, 1);
+        }
+
+        for(Map.Entry element: hashMap.entrySet())
+            alphabets.add(new Alphabet((char) element.getKey(), (int) element.getValue()));
+
+        alphabets.sort((o1, o2) -> {
+            if (o1.count != o2.count) return o2.count - o1.count;
+            else return Character.toString(o1.letter).compareTo(Character.toString(o2.letter));
+        });
+
+        for (Alphabet alphabet : alphabets) {
+            for (int i = 0; i < alphabet.count; i++)
+                builder.append(alphabet.letter);
+        }
+
+        return builder.toString();
+    }
+}