diff --git a/3042-count-prefix-and-suffix-pairs-i/README.md b/3042-count-prefix-and-suffix-pairs-i/README.md new file mode 100644 index 0000000..385488a --- /dev/null +++ b/3042-count-prefix-and-suffix-pairs-i/README.md @@ -0,0 +1,51 @@ +

3042. Count Prefix and Suffix Pairs I

Easy

You are given a 0-indexed string array words.

+ +

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

+ + + +

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:

+ +