Package g1701_1800.s1759_count_number_of_homogenous_substrings

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    1759 - Count Number of Homogenous Substrings.

    Medium

    Given a string s, return the number of homogenous substrings of s. Since the answer may be too large, return it modulo <code>10<sup>9</sup> + 7</code>.

    A string is homogenous if all the characters of the string are the same.

    A substring is a contiguous sequence of characters within a string.

    Example 1:

    Input: s = "abbcccaa"

    Output: 13

    Explanation: The homogenous substrings are listed as below:

    "a" appears 3 times.

    "aa" appears 1 time.

    "b" appears 2 times.

    "bb" appears 1 time.

    "c" appears 3 times.

    "cc" appears 2 times.

    "ccc" appears 1 time.

    3 + 1 + 2 + 1 + 3 + 2 + 1 = 13.

    Example 2:

    Input: s = "xy"

    Output: 2

    Explanation: The homogenous substrings are "x" and "y".

    Example 3:

    Input: s = "zzzzz"

    Output: 15

    Constraints:

    • <code>1 <= s.length <= 10<sup>5</sup></code>

    • s consists of lowercase letters.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer countHomogenous(String s)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait