leetcode

commit 03ca5c6054084ae3997c481efbc6e8eeb31a005c
parent 47a601b11c9e02232e12ac7f90b04ea7a1a259bd
Author: Jack Sangdahl <jack@pngu.org>
Date:   Wed, 12 Nov 2025 22:23:09 -0700

810. chalkboard xor game

Diffstat:
A
chalkboard_xor_game.c
 | 
28
++++++++++++++++++++++++++++
A
chalkboard_xor_game.py
 | 
32
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2 files changed, 60 insertions(+), 0 deletions(-)
diff --git a/chalkboard_xor_game.c b/chalkboard_xor_game.c
@@ -0,0 +1,28 @@
+// 810. Chalkboard XOR Game
+#include "leetcode.h"
+
+/*
+ * you are given an array of integers 'nums' that represents the numbers written
+ * on a chalboard. alice and bob take turns erasing exactly one number from the
+ * chalboard, with alice starting first. if erasing a number causes the bitwise
+ * xor of all the elements of the chalboard to become 0, then the player loses.
+ * the bitwise xor of one element is that element itself, and the bitwise xor of
+ * no elements is 0. also, if any player starts their turn with the bitwise xor
+ * of all the elements of the Chalkboard equal to 0 then that player wins.
+ * return true if and only if alice wins the game, assuming both players play
+ * optimally.
+ */
+
+bool xorGame(int *nums, int numsSize) {
+  int x = 0;
+  for (int i = 0; i < numsSize; i++)
+    x ^= nums[i];
+  return !x || !(numsSize % 2);
+}
+
+int main() {
+  int n1[] = {1, 1, 2}, n2[] = {0, 1}, n3[] = {1, 2, 3};
+  printf("%d\n", xorGame(n1, ARRAY_SIZE(n1))); // expect: 0
+  printf("%d\n", xorGame(n2, ARRAY_SIZE(n2))); // expect: 1
+  printf("%d\n", xorGame(n3, ARRAY_SIZE(n3))); // expect: 1
+}
diff --git a/chalkboard_xor_game.py b/chalkboard_xor_game.py
@@ -0,0 +1,32 @@
+# 810. Chalkboard XOR Game
+
+"""
+you are given an array of integers 'nums' that represents the numbers written
+on a chalboard. alice and bob take turns erasing exactly one number from the
+chalboard, with alice starting first. if erasing a number causes the bitwise
+xor of all the elements of the chalboard to become 0, then the player loses.
+the bitwise xor of one element is that element itself, and the bitwise xor of
+no elements is 0. also, if any player starts their turn with the bitwise xor
+of all the elements of the Chalkboard equal to 0 then that player wins.
+return true if and only if alice wins the game, assuming both players play
+optimally.
+"""
+
+
+class Solution(object):
+    def xorGame(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: bool
+        """
+        x = 0
+        for i in nums:
+            x ^= i
+        return x == 0 or len(nums) % 2 == 0
+
+
+if __name__ == "__main__":
+    obj = Solution()
+    print(obj.xorGame(nums=[1, 1, 2]))
+    print(obj.xorGame(nums=[0, 1]))
+    print(obj.xorGame(nums=[1, 2, 3]))