Sync LeetCode submission Runtime - 11 ms (47.36%), Memory - 18.1 MB (85.49%)

Author: jimit105

3227-find-missing-and-repeated-values/README.md

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+<p>You are given a <strong>0-indexed</strong> 2D integer matrix <code><font face="monospace">grid</font></code> of size <code>n * n</code> with values in the range <code>[1, n<sup>2</sup>]</code>. Each integer appears <strong>exactly once</strong> except <code>a</code> which appears <strong>twice</strong> and <code>b</code> which is <strong>missing</strong>. The task is to find the repeating and missing numbers <code>a</code> and <code>b</code>.</p>
+
+<p>Return <em>a <strong>0-indexed </strong>integer array </em><code>ans</code><em> of size </em><code>2</code><em> where </em><code>ans[0]</code><em> equals to </em><code>a</code><em> and </em><code>ans[1]</code><em> equals to </em><code>b</code><em>.</em></p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> grid = [[1,3],[2,2]]
+<strong>Output:</strong> [2,4]
+<strong>Explanation:</strong> Number 2 is repeated and number 4 is missing so the answer is [2,4].
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> grid = [[9,1,7],[8,9,2],[3,4,6]]
+<strong>Output:</strong> [9,5]
+<strong>Explanation:</strong> Number 9 is repeated and number 5 is missing so the answer is [9,5].
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>2 &lt;= n == grid.length == grid[i].length &lt;= 50</code></li>
+	<li><code>1 &lt;= grid[i][j] &lt;= n * n</code></li>
+	<li>For all <code>x</code> that <code>1 &lt;= x &lt;= n * n</code> there is exactly one <code>x</code> that is not equal to any of the grid members.</li>
+	<li>For all <code>x</code> that <code>1 &lt;= x &lt;= n * n</code> there is exactly one <code>x</code> that is equal to exactly two of the grid members.</li>
+	<li>For all <code>x</code> that <code>1 &lt;= x &lt;= n * n</code> except two of them there is exatly one pair of <code>i, j</code> that <code>0 &lt;= i, j &lt;= n - 1</code> and <code>grid[i][j] == x</code>.</li>
+</ul>

3227-find-missing-and-repeated-values/solution.py

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+# Approach: Hash Map
+
+# Time: O(n^2)
+# Space: O(n^2)
+
+class Solution:
+    def findMissingAndRepeatedValues(self, grid: List[List[int]]) -> List[int]:
+        n = len(grid)
+        freq = {}
+
+        for row in grid:
+            for num in row:
+                freq[num] = freq.get(num, 0) + 1
+
+        for num in range(1, n * n + 1):
+            if num not in freq:
+                missing = num
+            elif freq[num] == 2:
+                repeat = num
+
+        return [repeat, missing]
+