leetcode

commit ef565e321f29ebb749d8fdad74a0f7d7105ddee0
parent 534ded84da3cbdf9c51b3f65dedde4321541a376
Author: Jack Sangdahl <jack@pngu.org>
Date:   Tue, 17 Feb 2026 20:05:02 -0700

693. binary number with alternating bits

Diffstat:
M
binary_num_alter_bits.c
 | 
18
+++++++++++++-----
M
binary_num_alter_bits.py
 | 
4
++--

2 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/binary_num_alter_bits.c b/binary_num_alter_bits.c
@@ -1,5 +1,7 @@
 // 693. Binary Number with Alternating Bits
 #include "leetcode.h"
+#include <cassert>
+#include <stdio.h>
 
 /*
  * given a positive integer, check whether it has alternating bits: namely if
@@ -7,12 +9,18 @@
  */
 
 bool hasAlternatingBits(int n) {
-  long long int x = n ^ (n >> 1);
-  return !(x & (x + 1));
+  n ^= (n >> 1);
+  return !(n & n + 1);
 }
 
 int main() {
-  printf("%d\n", hasAlternatingBits(5));  // expect: 1
-  printf("%d\n", hasAlternatingBits(7));  // expect: 0
-  printf("%d\n", hasAlternatingBits(11)); // expect: 0
+  bool r1 = hasAlternatingBits(5);
+  bool r2 = hasAlternatingBits(7);
+  bool r3 = hasAlternatingBits(11);
+  printf("%d\n", r1); // expect: 1
+  assert(r1 == true);
+  printf("%d\n", r2); // expect: 0
+  assert(r2 == false);
+  printf("%d\n", r3); // expect: 0
+  assert(r3 == true);
 }
diff --git a/binary_num_alter_bits.py b/binary_num_alter_bits.py
@@ -12,8 +12,8 @@ class Solution(object):
         :type n: int
         :rtype: bool
         """
-        x = n ^ (n >> 1)
-        return (x & (x + 1)) == 0
+        n ^= n >> 1
+        return (n & n + 1) == 0
 
 
 if __name__ == "__main__":