leetcode

commit 318f6f2fa77c323580e80fec30b221b1f8d253e5
parent ec44665d6c0a4bcd1402ece43e6885f6edd1cfba
Author: Jack Sangdahl <jack@pngu.org>
Date:   Wed, 22 Oct 2025 22:03:30 -0600

3461. check if digits are equal in string after operations 1

Diffstat:
A
check_digits_eq_str_op1.c
 | 
33
+++++++++++++++++++++++++++++++++
A
check_digits_eq_str_op1.py
 | 
32
++++++++++++++++++++++++++++++++

2 files changed, 65 insertions(+), 0 deletions(-)
diff --git a/check_digits_eq_str_op1.c b/check_digits_eq_str_op1.c
@@ -0,0 +1,33 @@
+// 3461. Check If Digits Are Equal in String After Operations I
+#include "leetcode.h"
+
+/*
+ * you are given a string 's' consisting of digits. perform the following
+ * operation repeatedly until the string has exactly two digits: for each pair
+ * of consecutive digits in 's', starting from the first digit, calculate a new
+ * digit as the sum of the two digits modulo 10. replace 's' with the sequence
+ * of newly calcluated digits, maintaining their order in which they were
+ * computed. return true if the final two digits in 's' are the same; otherwise
+ * return false.
+ */
+
+bool hasSameDigits(char *s) {
+  if (*(s + 2) == '\0')
+    return s[0] == s[1];
+  char *tmp = s;
+  while (*(tmp + 1) != '\0') {
+    (*tmp) = (((*tmp - '0') + (*(tmp + 1) - '0')) % 10) + '0';
+    tmp++;
+  }
+  *(tmp) = '\0';
+  return hasSameDigits(s);
+}
+
+int main() {
+  char *s1i = "3902", *s1 = strdup(s1i);
+  char *s2i = "34789", *s2 = strdup(s2i);
+  printf("%d\n", hasSameDigits(s1)); // expect: 1
+  printf("%d\n", hasSameDigits(s2)); // expect: 0
+  free(s1);
+  free(s2);
+}
diff --git a/check_digits_eq_str_op1.py b/check_digits_eq_str_op1.py
@@ -0,0 +1,32 @@
+# 3461. Check If Digits Are Equal in String After Operations I
+
+"""
+you are given a string 's' consisting of digits. perform the following
+operation repeatedly until the string has exactly two digits: for each pair
+of consecutive digits in 's', starting from the first digit, calculate a new
+digit as the sum of the two digits modulo 10. replace 's' with the sequence
+of newly calcluated digits, maintaining their order in which they were
+computed. return true if the final two digits in 's' are the same; otherwise
+return false.
+"""
+
+
+class Solution(object):
+    def hasSameDigits(self, s):
+        """
+        :type s: str
+        :rtype: bool
+        """
+        while len(s) != 2:
+            tmp = ""
+            for i in range(1, len(s)):
+                j = ((ord(s[i]) - ord("a")) + (ord(s[i - 1]) - ord("a"))) % 10
+                tmp += chr(j + ord("a"))
+            s = tmp
+        return s[0] == s[1]
+
+
+if __name__ == "__main__":
+    obj = Solution()
+    print(obj.hasSameDigits(s="3902"))
+    print(obj.hasSameDigits(s="34789"))