Package g3001_3100.s3045_count_prefix_and_suffix_pairs_ii

Class Solution

java.lang.Object
g3001_3100.s3045_count_prefix_and_suffix_pairs_ii.Solution
public class Solution extends java.lang.Object
3045 - Count Prefix and Suffix Pairs II.

Hard

You are given a 0-indexed string array words.

Let’s define a boolean function isPrefixAndSuffix that takes two strings, str1 and str2:

  • isPrefixAndSuffix(str1, str2) returns true if str1 is both a prefix and a suffix of str2, and false otherwise.

For example, isPrefixAndSuffix("aba", "ababa") is true because "aba" is a prefix of "ababa" and also a suffix, but isPrefixAndSuffix("abc", "abcd") is false.

Return an integer denoting the number of index pairs (i_,_ j) such that i < j, and isPrefixAndSuffix(words[i], words[j]) is true.

Example 1:

Input: words = [“a”,“aba”,“ababa”,“aa”]

Output: 4

Explanation: In this example, the counted index pairs are:

i = 0 and j = 1 because isPrefixAndSuffix(“a”, “aba”) is true.

i = 0 and j = 2 because isPrefixAndSuffix(“a”, “ababa”) is true.

i = 0 and j = 3 because isPrefixAndSuffix(“a”, “aa”) is true.

i = 1 and j = 2 because isPrefixAndSuffix(“aba”, “ababa”) is true.

Therefore, the answer is 4.

Example 2:

Input: words = [“pa”,“papa”,“ma”,“mama”]

Output: 2

Explanation: In this example, the counted index pairs are:

i = 0 and j = 1 because isPrefixAndSuffix(“pa”, “papa”) is true.

i = 2 and j = 3 because isPrefixAndSuffix(“ma”, “mama”) is true.

Therefore, the answer is 2.

Example 3:

Input: words = [“abab”,“ab”]

Output: 0

Explanation: In this example, the only valid index pair is i = 0 and j = 1, and isPrefixAndSuffix(“abab”, “ab”) is false.

Therefore, the answer is 0.

Constraints:

  • 1 <= words.length <= 105
  • 1 <= words[i].length <= 105
  • words[i] consists only of lowercase English letters.
  • The sum of the lengths of all words[i] does not exceed 5 * 105.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    long
    countPrefixSuffixPairs(java.lang.String[] words)
     

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • countPrefixSuffixPairs

      public long countPrefixSuffixPairs(java.lang.String[] words)