// 3042. Count Prefix and Suffix Pairs I #include "leetcode.h" /* * you are given a 0-indexed string array 'words'. let's define a boolean * function 'isPrefixSuffix' that takes two strings 'str1' and 'str2'. * 'isPrefixSuffix()' returns true if 'str1' is both a prefix and suffix of * 'str2', and false otherwise. return an integer denoting the number of index * pairs '(i, j)' such that 'i < j' and 'isPrefixSuffix(words[i], words[j])' is * true. */ bool isPrefixAndSuffix(char *str1, char *str2) { int n = strlen(str1), m = strlen(str2); for (int i = 0, j = 0; str1[i]; i++, j++) if (str1[i] != str2[j]) return false; for (int i = n - 1, j = m - 1; j >= 0 && i >= 0; i--, j--) if (str1[i] != str2[j]) return false; return true; } int countPrefixSuffixPairs(char **words, int wordsSize) { int cnt = 0; for (int i = 0; i < wordsSize; i++) for (int j = i + 1; j < wordsSize; j++) if (isPrefixAndSuffix(words[i], words[j])) cnt++; return cnt; } int main() { char *w1[] = {"a", "aba", "ababa", "aa"}, *w2[] = {"pa", "papa", "ma", "mama"}, *w3[] = {"abab", "ab"}; printf("%d\n", countPrefixSuffixPairs((char **)w1, ARRAY_SIZE(w1))); // expect: 4 printf("%d\n", countPrefixSuffixPairs((char **)w2, ARRAY_SIZE(w2))); // expect: 2 printf("%d\n", countPrefixSuffixPairs((char **)w3, ARRAY_SIZE(w3))); // expect: 0 }