leetcode

commit 337963533fc481a12482a6524b197e71084087ce
parent 28502983118aa4df2e4ce7db1dcf5a69a2f24d21
Author: Jack Sangdahl <jack@pngu.org>
Date:   Sun, 29 Mar 2026 20:34:18 -0600

2840. check if strings can be made equal with operations 2

Diffstat:
A
check_str_eq_op2.c
 | 
35
+++++++++++++++++++++++++++++++++++
A
check_str_eq_op2.py
 | 
24
++++++++++++++++++++++++

2 files changed, 59 insertions(+), 0 deletions(-)
diff --git a/check_str_eq_op2.c b/check_str_eq_op2.c
@@ -0,0 +1,35 @@
+// 2840. Check if Strings Can be Made Equal With Operations II
+#include "leetcode.h"
+
+/*
+ * you are given two strings 's1' and 's2' both of length 'n' consisting of
+ * lowercase english letters. you can apply the following operation on any of
+ * the two strings any number of times. choose any two indices 'i' and 'j' such
+ * that 'i < j' and the difference 'j - i' is even, then swap the two characters
+ * at those indices in the string. return true if you can make the strings 's1'
+ * and 's2' equal, otherwise return false.
+ */
+
+bool checkStrings(char *s1, char *s2) {
+  int n = strlen(s1), cnts[256] = {0};
+  for (int i = 0; i < n; i++) {
+    int offset = (i & 1) << 7;
+    cnts[offset + s1[i]]++;
+    cnts[offset + s2[i]]--;
+  }
+  for (int i = 0; i < 256; i++)
+    if (cnts[i])
+      return false;
+  return true;
+}
+
+int main() {
+  char *s11 = "abcdba", *s21 = "cabdab";
+  char *s12 = "abe", *s22 = "bea";
+  bool r1 = checkStrings(s11, s21);
+  bool r2 = checkStrings(s12, s22);
+  printf("%d\n", r1);
+  assert(r1 == true);
+  printf("%d\n", r2);
+  assert(r2 == false);
+}
diff --git a/check_str_eq_op2.py b/check_str_eq_op2.py
@@ -0,0 +1,24 @@
+# 2840. Check if Strings Can be Made Equal With Operations II
+from collections import Counter
+
+"""
+you are given two strings 's1' and 's2' both of length 'n' consisting of
+lowercase english letters. you can apply the following operation on any of
+the two strings any number of times. choose any two indices 'i' and 'j' such
+that 'i < j' and the difference 'j - i' is even, then swap the two characters
+at those indices in the string. return true if you can make the strings 's1'
+and 's2' equal, otherwise return false.
+"""
+
+
+class Solution:
+    def checkStrings(self, s1: str, s2: str) -> bool:
+        return Counter(s1[::2]) == Counter(s2[::2]) and Counter(s1[1::2]) == Counter(
+            s2[1::2]
+        )
+
+
+if __name__ == "__main__":
+    obj = Solution()
+    print(obj.checkStrings(s1="abcdba", s2="cabdab"))
+    print(obj.checkStrings(s1="abe", s2="bea"))