solved problem12

javaProblems/problem12/Solution.java

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+public class Solution {
+    public int solve(int n) {
+        String string = Integer.toBinaryString(n);
+        int count = 0;
+        for (char digit : string.toCharArray()) {
+            if (digit == '1') {
+                count++;
+            }
+        }
+        return count;
+    }
+}

javaProblems/problem12/Test.java

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+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class Test {
+    public static void main(String[] args) {
+        Logger logger = Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);
+        Solution solution = new Solution();
+
+        // Test case 1
+        int n = 00000000000000000000000000001011;
+        int ans1 = solution.solve(n);
+        if (ans1 != 3) {
+            logger.log(Level.SEVERE, "Test Case 1: Wrong solution!");
+            System.exit(1);
+        }
+
+        // Test case 2
+        int n2 = 00000000000000000000000010000000;
+        int ans2 = solution.solve(n2);
+        if (ans2 != 1) {
+            logger.log(Level.SEVERE, "Test Case 2: Wrong solution!");
+            System.exit(1);
+        }
+
+        System.out.print("All Testcases passed!");
+    }
+}

javaProblems/problem12/readme.md

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+# Number of 1 Bits
+
+## Problem Statement
+Write a function that takes the `binary representation` of an unsigned integer and returns the number of `'1'` bits it has (also known as the `Hamming weight`).
+
+```
+# Example 1
+
+Input: n = 00000000000000000000000000001011
+Output: 3
+
+
+# Example 2
+
+Input: n = 00000000000000000000000010000000
+Output: 1
+
+```