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1358. Number of Substrings Containing All Three Characters

Difficulty Topics

Description

Given a string s consisting only of characters a, b and c.

Return the number of substrings containing at least one occurrence of all these characters a, b and c.

 

Example 1:

Input: s = "abcabc"
Output: 10
Explanation: The substrings containing at least one occurrence of the characters a, b and c are "abc", "abca", "abcab", "abcabc", "bca", "bcab", "bcabc", "cab", "cabc" and "abc" (again).

Example 2:

Input: s = "aaacb"
Output: 3
Explanation: The substrings containing at least one occurrence of the characters a, b and c are "aaacb", "aacb" and "acb".

Example 3:

Input: s = "abc"
Output: 1

 

Constraints:

  • 3 <= s.length <= 5 x 10^4
  • s only consists of a, b or c characters.

Solution

number-of-substrings-containing-all-three-characters.py
class Solution:
    def numberOfSubstrings(self, s: str) -> int:
        mp = {c:0 for c in "abc"}
        res = i = 0

        for j, c in enumerate(s):
            mp[c] += 1

            while all(mp.values()):
                mp[s[i]] -= 1
                i += 1

            res += i

        return res