Create number-of-equal-count-substrings.py

Author: kamyu104

Python/number-of-equal-count-substrings.py

@@ -0,0 +1,21 @@
+# Time:  O(26 * n) = O(n)
+# Space: O(26) = O(1)
+
+class Solution(object):
+    def equalCountSubstrings(self, s, count):
+        """
+        :type s: str
+        :type count: int
+        :rtype: int
+        """
+        result = 0
+        for l in xrange(1, min(len(set(s)), len(s)//count)+1):
+            cnt, equal_cnt = collections.Counter(), 0
+            for i, c in enumerate(s):
+                cnt[c] += 1
+                equal_cnt += (cnt[c] == count)
+                if count*l <= i:
+                    equal_cnt -= (cnt[s[i-count*l]] == count)
+                    cnt[s[i-count*l]] -= 1
+                result += (equal_cnt == l)
+        return result