test: add LeetCode 1941 with tests, complexity docs, and migration

README.md

@@ -44,11 +44,11 @@ Each problem follows this structure:
 
 ## Solutions
 
-📊 **Statistics**: 53 problems solved (migrated to new structure)
+📊 **Statistics**: 54 problems solved (migrated to new structure)
 
 | Difficulty | Count |
 |------------|-------|
-| Easy       | 37    |
+| Easy       | 38    |
 | Medium     | 15    |
 | Hard       | 1     |
 

docs/EASY.md

@@ -1,6 +1,6 @@
 # Easy Problems
 
-Total: 37 problems solved
+Total: 38 problems solved
 
 ## Solutions
 
@@ -34,6 +34,7 @@ Total: 37 problems solved
 | 1672 | [Richest Customer Wealth](https://leetcode.com/problems/richest-customer-wealth/) | [RichestCustomerWealth1672.java](../src/main/java/com/leetcode/easy/RichestCustomerWealth1672.java) | [RichestCustomerWealth1672Test.java](../src/test/java/com/leetcode/easy/RichestCustomerWealth1672Test.java) |
 | 1773 | [Count Items Matching a Rule](https://leetcode.com/problems/count-items-matching-a-rule/) | [CountItemsMatchingARule1773.java](../src/main/java/com/leetcode/easy/CountItemsMatchingARule1773.java) | [CountItemsMatchingARule1773Test.java](../src/test/java/com/leetcode/easy/CountItemsMatchingARule1773Test.java) |
 | 1816 | [Truncate Sentence](https://leetcode.com/problems/truncate-sentence/) | [TruncateSentence1816.java](../src/main/java/com/leetcode/easy/TruncateSentence1816.java) | [TruncateSentence1816Test.java](../src/test/java/com/leetcode/easy/TruncateSentence1816Test.java) |
+| 1941 | [Check if All Characters Have Equal Number of Occurrences](https://leetcode.com/problems/check-if-all-characters-have-equal-number-of-occurrences/) | [CheckIfAllCharactersHaveEqualNumberOfOccurrences1941.java](../src/main/java/com/leetcode/easy/CheckIfAllCharactersHaveEqualNumberOfOccurrences1941.java) | [CheckIfAllCharactersHaveEqualNumberOfOccurrences1941Test.java](../src/test/java/com/leetcode/easy/CheckIfAllCharactersHaveEqualNumberOfOccurrences1941Test.java) |
 | 2011 | [Final Value of Variable After Performing Operations](https://leetcode.com/problems/final-value-of-variable-after-performing-operations/) | [FinalValueOfVariableAfterPerformingOperations2011.java](../src/main/java/com/leetcode/easy/FinalValueOfVariableAfterPerformingOperations2011.java) | [FinalValueOfVariableAfterPerformingOperations2011Test.java](../src/test/java/com/leetcode/easy/FinalValueOfVariableAfterPerformingOperations2011Test.java) |
 | 2032 | [Two Out of Three](https://leetcode.com/problems/two-out-of-three/) | [TwoOutOfThree2032.java](../src/main/java/com/leetcode/easy/TwoOutOfThree2032.java) | [TwoOutOfThree2032Test.java](../src/test/java/com/leetcode/easy/TwoOutOfThree2032Test.java) |
 | 2124 | [Check if All A's Appears Before All B's](https://leetcode.com/problems/check-if-all-as-appears-before-all-bs/) | [CheckIfAllAsAppearsBeforeAllBs2124.java](../src/main/java/com/leetcode/easy/CheckIfAllAsAppearsBeforeAllBs2124.java) | [CheckIfAllAsAppearsBeforeAllBs2124Test.java](../src/test/java/com/leetcode/easy/CheckIfAllAsAppearsBeforeAllBs2124Test.java) |

src/main/java/com/leetcode/easy/CheckIfAllCharactersHaveEqualNumberOfOccurrences1941.java

@@ -0,0 +1,32 @@
+// Tags: String, Hash Table
+package com.leetcode.easy;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+
+public class CheckIfAllCharactersHaveEqualNumberOfOccurrences1941 {
+    /**
+     * Checks if all characters in the string have equal number of occurrences.
+     *
+     * <p>Approach:
+     * <ul>
+     *   <li>Use HashMap to count frequency of each character</li>
+     *   <li>Put all frequency values into HashSet</li>
+     *   <li>If HashSet size is 1, all characters have same occurrence count</li>
+     * </ul>
+     *
+     * <p>Time Complexity: O(n) where n is the length of the string, single pass required
+     * <p>Space Complexity: O(1) as at most 26 unique characters are stored (constraint: lowercase letters only)
+     *
+     * @param s input string containing only lowercase English letters
+     * @return true if all characters appear the same number of times, false otherwise
+     */
+    public boolean areOccurrencesEqual(String s) {
+        Map<Character, Integer> freq = new HashMap<>();
+        for (char c : s.toCharArray()) {
+            freq.put(c, freq.getOrDefault(c, 0) + 1);
+        }
+        return new HashSet<>(freq.values()).size() == 1;
+    }
+}

src/test/java/com/leetcode/easy/CheckIfAllCharactersHaveEqualNumberOfOccurrences1941Test.java

@@ -0,0 +1,23 @@
+package com.leetcode.easy;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class CheckIfAllCharactersHaveEqualNumberOfOccurrences1941Test {
+
+    @Test
+    void testAreOccurrencesEqualExample1() {
+        CheckIfAllCharactersHaveEqualNumberOfOccurrences1941 solution = new CheckIfAllCharactersHaveEqualNumberOfOccurrences1941();
+        String s = "abacbc";
+        boolean result = solution.areOccurrencesEqual(s);
+        assertTrue(result, "The characters 'a', 'b', and 'c' should all occur 2 times in s");
+    }
+
+    @Test
+    void testAreOccurrencesEqualExample2() {
+        CheckIfAllCharactersHaveEqualNumberOfOccurrences1941 solution = new CheckIfAllCharactersHaveEqualNumberOfOccurrences1941();
+        String s = "aaabb";
+        boolean result = solution.areOccurrencesEqual(s);
+        assertFalse(result, "'a' occurs 3 times while 'b' occurs 2 times, which is not equal");
+    }
+}