feat: counting-bits

Author: minji-go

counting-bits/minji-go.java

@@ -0,0 +1,20 @@
+/**
+ * <a href="https://leetcode.com/problems/counting-bits/">week14-1. counting-bits</a>
+ * <li>Description: Given an integer n, return an array ans of length n + 1 such that for each i (0 <= i <= n), ans[i] is the number of 1's in the binary representation of i</li>
+ * <li>Topics: Dynamic Programming, Bit Manipulation</li>
+ * <li>Time Complexity: O(N), Runtime 2ms       </li>
+ * <li>Space Complexity: O(N), Memory 46.64MB   </li>
+ */
+class Solution {
+    public int[] countBits(int n) {
+        int[] count = new int[n + 1];
+
+        int offset = 1;
+        for (int i = 1; i <= n; i++) {
+            if (i == offset * 2) offset *= 2;
+            count[i] = count[i - offset] + 1;
+        }
+
+        return count;
+    }
+}