Sync LeetCode submission Runtime - 479 ms (6.32%), Memory - 7.9 MB (98.33%)

Author: koralkulacoglu

LeetCode/1617-stone-game-iv/README.md

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+<p>Alice and Bob take turns playing a game, with Alice starting first.</p>
+
+<p>Initially, there are <code>n</code> stones in a pile. On each player&#39;s turn, that player makes a <em>move</em> consisting of removing <strong>any</strong> non-zero <strong>square number</strong> of stones in the pile.</p>
+
+<p>Also, if a player cannot make a move, he/she loses the game.</p>
+
+<p>Given a positive integer <code>n</code>, return <code>true</code> if and only if Alice wins the game otherwise return <code>false</code>, assuming both players play optimally.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 1
+<strong>Output:</strong> true
+<strong>Explanation: </strong>Alice can remove 1 stone winning the game because Bob doesn&#39;t have any moves.</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 2
+<strong>Output:</strong> false
+<strong>Explanation: </strong>Alice can only remove 1 stone, after that Bob removes the last one winning the game (2 -&gt; 1 -&gt; 0).
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 4
+<strong>Output:</strong> true
+<strong>Explanation:</strong> n is already a perfect square, Alice can win with one move, removing 4 stones (4 -&gt; 0).
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= n &lt;= 10<sup>5</sup></code></li>
+</ul>

LeetCode/1617-stone-game-iv/solution.cpp

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+class Solution {
+    int n = 1e5;
+    array<bool, (int)1e5+1> dp;
+    bool comp = false;
+
+    void precomp() {
+        dp.fill(false);
+        dp[1] = true;
+        for (int i=2; i<=n; i++) {
+            for (int s=1; s*s<=i; s++) {
+                if (!dp[i - s*s]) {
+                    dp[i] = true;
+                    break;
+                }
+            }
+        }
+    }
+    
+public:
+    bool winnerSquareGame(int n) {
+        if (!comp) {
+            precomp();
+            comp = true;
+        }
+
+        return dp[n];
+    }
+};