[LeetCode Sync] Runtime - 0 ms (100.00%), Memory - 17.8 MB (39.35%)

Author: NinePiece2

Solutions/0400-nth-digit/README.md

@@ -0,0 +1,24 @@
+<p>Given an integer <code>n</code>, return the <code>n<sup>th</sup></code> digit of the infinite integer sequence <code>[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ...]</code>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 3
+<strong>Output:</strong> 3
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 11
+<strong>Output:</strong> 0
+<strong>Explanation:</strong> The 11<sup>th</sup> digit of the sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... is a 0, which is part of the number 10.
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= n &lt;= 2<sup>31</sup> - 1</code></li>
+</ul>

Solutions/0400-nth-digit/solution.py

@@ -0,0 +1,11 @@
+class Solution:
+    def findNthDigit(self, n: int) -> int:
+        val, count = 1, 9
+        while val * count < n:
+            n -= val * count
+            val += 1
+            count *= 10
+        
+        num = 10 ** (val - 1) + ((n - 1) // val)
+        index = (n - 1) % val
+        return int(str(num)[index])