Counting Coding Problems

Count occurrences and frequencies

166
Total Problems
58
Easy
87
Medium
20
Hard
Start Practicing
1358

Master DSA Topics - February, 2026

Practice problems across 75+ categories

Counting Coding Problems

Practice problems frequently asked at Counting 166 problems | 58 Easy | 87 Medium | 20 Hard

# Problem Difficulty Topics
151 Stone Game IX Medium
ArrayMathGreedy
152 Subarrays with K Different Integers Hard
ArrayHash TableSliding Window
153 Subdomain Visit Count Medium
ArrayHash TableString
154 Substrings of Size Three with Distinct Characters Easy
Hash TableStringSliding Window
155 Substrings That Begin and End With the Same Letter Medium
Hash TableMathString
156 Sum of Beauty of All Substrings Medium
Hash TableStringCounting
157 Sum of Digit Differences of All Pairs Medium
ArrayHash TableMath
158 Sum of Prefix Scores of Strings Hard
ArrayStringTrie
159 Sum of Unique Elements Easy
ArrayHash TableCounting
160 Task Scheduler Medium
ArrayHash TableGreedy
161 The Number of Good Subsets Hard
ArrayHash TableMath
162 Top K Frequent Elements Medium
ArrayHash TableDivide and Conquer
163 Top K Frequent Words Medium
ArrayHash TableString
164 Total Characters in String After Transformations I Medium
Hash TableMathString
165 Total Characters in String After Transformations II Hard
Hash TableMathString
Showing 151-165 of 166
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public class MyFirstJavaProgram { Edit & Run

   /* This is my first java program.
    * This will print 'Hello, World!' as the output
    */

   public static void main(String []args) {
      System.out.println("Hello, World!"); // prints
   }
}

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