// 3335. Total Characters in String After Transformations I #include "leetcode.h" /* * you are given a string 's' and an integer 't' representing the number of * transformations to perform. in one transformation, every character in 's' is * replaced according to the following rules: if the character is 'z', replace * it with the string 'ab'. otherwise, replace it with the next character in the * alphabet. return the length of the resulting string after exactly 't' * transformations. since the answer may be very large, return it modulo 10^9 * + 7. */ int lengthAfterTransformations(char *s, int t) { const int mod = 1e9 + 7; int cnt[26] = {0}, n = strlen(s); for (int i = 0; i < n; i++) cnt[s[i] - 'a']++; for (int i = 0; i < t; i++) { int tmp[26] = {0}; for (int j = 0; j < 26; j++) { if (j == 25) { tmp[0] = (tmp[0] + cnt[j]) % mod; tmp[1] = (tmp[1] + cnt[j]) % mod; } else tmp[j + 1] = (tmp[j + 1] + cnt[j]) % mod; } memcpy(cnt, tmp, sizeof(cnt)); } int ans = 0; for (int i = 0; i < 26; i++) ans = (ans + cnt[i]) % mod; return ans; } int main() { char *s1 = "abcyy", *s2 = "azbk"; printf("%d\n", lengthAfterTransformations(s1, 2)); // expect: 7 printf("%d\n", lengthAfterTransformations(s2, 1)); // expect: 5 }