leetcode

commit d200dac0fb0717dec93bfad66d467f7dccf1b049
parent e820af62f134a5cfd0a02b583d24207af3379b08
Author: Jack Sangdahl <jack@pngu.org>
Date:   Sat,  3 May 2025 01:12:52 -0600

1007. minimum domino rotations for equal row

Diffstat:
A
min_domino_rotation_eq_row.c
 | 
40
++++++++++++++++++++++++++++++++++++++++
A
min_domino_rotation_eq_row.py
 | 
30
++++++++++++++++++++++++++++++

2 files changed, 70 insertions(+), 0 deletions(-)
diff --git a/min_domino_rotation_eq_row.c b/min_domino_rotation_eq_row.c
@@ -0,0 +1,40 @@
+// 1007. Minimum Domino Rotations For Equal Row
+#include "leetcode.h"
+
+/*
+ * in a row of dominoes, 'tops[i]' and 'bottoms[i]' represents the top and
+ * bottom halves of the i'th domino. we may rotate the i'th domino so that
+ * 'tops[i]' and 'bottoms[i]' swap values. return the minimum number of
+ * rotations so that all values in 'tops' are the same, or all values in
+ * 'bottoms' are the same. if it cannot be done, return -1.
+ */
+
+int minDominoRotations(int *tops, int topsSize, int *bottoms, int bottomsSize) {
+  int mask = 0x7E, num = -1, a = 0, b = 0;
+  for (int i = 0; i < topsSize; i++) {
+    mask &= ((1 << tops[i]) | (1 << bottoms[i]));
+    if (!mask)
+      return -1;
+  }
+  while (mask) {
+    num++;
+    mask >>= 1;
+  }
+  for (int i = 0; i < topsSize; i++) {
+    if (tops[i] == num)
+      a++;
+    if (bottoms[i] == num)
+      b++;
+  }
+  int max = a > b ? a : b;
+  return topsSize - max;
+}
+
+int main() {
+  int t1[] = {2, 1, 2, 4, 2, 2}, b1[] = {5, 2, 6, 2, 3, 2};
+  int t2[] = {3, 5, 1, 2, 3}, b2[] = {3, 6, 3, 3, 4};
+  printf("%d\n", minDominoRotations(t1, ARRAY_SIZE(t1), b1,
+                                    ARRAY_SIZE(b1))); // expect: 2
+  printf("%d\n", minDominoRotations(t2, ARRAY_SIZE(t2), b2,
+                                    ARRAY_SIZE(b2))); // expect: -1
+}
diff --git a/min_domino_rotation_eq_row.py b/min_domino_rotation_eq_row.py
@@ -0,0 +1,30 @@
+# 1007. Minimum Domino Rotations For Equal Row
+from functools import reduce
+
+"""
+in a row of dominoes, 'tops[i]' and 'bottoms[i]' represents the top and
+bottom halves of the i'th domino. we may rotate the i'th domino so that
+'tops[i]' and 'bottoms[i]' swap values. return the minimum number of
+rotations so that all values in 'tops' are the same, or all values in
+'bottoms' are the same. if it cannot be done, return -1.
+"""
+
+
+class Solution(object):
+    def minDominoRotations(self, tops, bottoms):
+        """
+        :type tops: List[int]
+        :type bottoms: List[int]
+        :rtype: int
+        """
+        s = reduce(set.__and__, (set(i) for i in zip(tops, bottoms)))
+        if not s:
+            return -1
+        x = s.pop()
+        return min(len(tops) - tops.count(x), len(bottoms) - bottoms.count(x))
+
+
+if __name__ == "__main__":
+    obj = Solution()
+    print(obj.minDominoRotations(tops=[2, 1, 2, 4, 2, 2], bottoms=[5, 2, 6, 2, 3, 2]))
+    print(obj.minDominoRotations(tops=[3, 5, 1, 2, 3], bottoms=[3, 6, 3, 3, 4]))