leetcode

commit 9aaab2ea9c483997ba3a9c1235cd38125fa68d69
parent 9e00d6582e7b3758610b8dab014180dc15171c00
Author: Jack Sangdahl <jack@pngu.org>
Date:   Thu,  1 Jan 2026 20:00:45 -0700

1525. number of good ways to split a string

Diffstat:
A
num_good_ways_split_str.c
 | 
33
+++++++++++++++++++++++++++++++++
A
num_good_ways_split_str.py
 | 
33
+++++++++++++++++++++++++++++++++

2 files changed, 66 insertions(+), 0 deletions(-)
diff --git a/num_good_ways_split_str.c b/num_good_ways_split_str.c
@@ -0,0 +1,33 @@
+// 1525. Number of Good Ways to Split a String
+#include "leetcode.h"
+
+/*
+ * you are given a string 's'. a split is called good if you can split 's' into
+ * two non-empty strings 's_left' and 's_right' where their concatenation is
+ * equal to 's' (ie. 's_left + s_right = s') and the number of distinct letters
+ * in 's_left' and 's_right' is the same. return the number of good splits you
+ * can make in 's'.
+ */
+
+int numSplits(char *s) {
+  int l_map[26] = {0}, r_map[26] = {0};
+  int cnt = 0, l_char = 0, r_char = 0, n = strlen(s);
+  for (int i = 0; i < n; i++)
+    if (!r_map[s[i] - 'a']++)
+      r_char++;
+  for (int i = 0; i < n - 1; i++) {
+    if (!l_map[s[i] - 'a']++)
+      l_char++;
+    if (!--r_map[s[i] - 'a'])
+      r_char--;
+    if (l_char == r_char)
+      cnt++;
+  }
+  return cnt;
+}
+
+int main() {
+  char *s1 = "aacaba", *s2 = "abcd";
+  printf("%d\n", numSplits(s1)); // expect: 2
+  printf("%d\n", numSplits(s2)); // expect: 1
+}
diff --git a/num_good_ways_split_str.py b/num_good_ways_split_str.py
@@ -0,0 +1,33 @@
+# 1525. Number of Good Ways to Split a String
+from collections import Counter
+
+"""
+you are given a string 's'. a split is called good if you can split 's' into
+two non-empty strings 's_left' and 's_right' where their concatenation is
+equal to 's' (ie. 's_left + s_right = s') and the number of distinct letters
+in 's_left' and 's_right' is the same. return the number of good splits you
+can make in 's'.
+"""
+
+
+class Solution(object):
+    def numSplits(self, s):
+        """
+        :type s: str
+        :rtype: int
+        """
+        l_map, r_map, cnt = Counter(), Counter(), 0
+        for i in s:
+            l_map[i] += 1
+            r_map[i] -= 1
+            if r_map[i] == 0:
+                del r_map[i]
+            if len(l_map) == len(r_map):
+                cnt += 1
+        return cnt
+
+
+if __name__ == "__main__":
+    obj = Solution()
+    print(obj.numSplits(s="aacaba"))
+    print(obj.numSplits(s="abcd"))