Sync LeetCode submission Runtime - 0 ms (100.00%), Memory - 17.6 MB (88.25%)

Author: jimit105

1889-check-if-number-is-a-sum-of-powers-of-three/README.md

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+<p>Given an integer <code>n</code>, return <code>true</code> <em>if it is possible to represent </em><code>n</code><em> as the sum of distinct powers of three.</em> Otherwise, return <code>false</code>.</p>
+
+<p>An integer <code>y</code> is a power of three if there exists an integer <code>x</code> such that <code>y == 3<sup>x</sup></code>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 12
+<strong>Output:</strong> true
+<strong>Explanation:</strong> 12 = 3<sup>1</sup> + 3<sup>2</sup>
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 91
+<strong>Output:</strong> true
+<strong>Explanation:</strong> 91 = 3<sup>0</sup> + 3<sup>2</sup> + 3<sup>4</sup>
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 21
+<strong>Output:</strong> false
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= n &lt;= 10<sup>7</sup></code></li>
+</ul>

1889-check-if-number-is-a-sum-of-powers-of-three/solution.py

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+# Approach 2: Optimized Iterative Approach
+
+# Time: O(log n)
+# Space: O(1)
+
+class Solution:
+    def checkPowersOfThree(self, n: int) -> bool:
+        power = 0
+
+        while 3 ** power <= n:
+            power += 1
+        
+        while n > 0:
+            if n >= 3 ** power:
+                n -= 3 ** power
+
+            # We cannot use the same power twice
+            if n >= 3 ** power:
+                return False
+
+            power -= 1
+
+        # n has reached 0
+        return True