// 2138. Divide a String Into Groups of Size k #include "leetcode.h" /* * a string 's' can be partitioned into groups of size 'k' using the following * procedure: the first group consists of the first 'k' characters of the * string, the second group consists of the next 'k' characters of the string, * ans so on. each element can be a part of exactly one group. for the last * group, if the string does not have 'k' characters remaining, a character * 'fill' is used to complete the group. note that the partition is done so that * after removing the 'fill' character from the last group, and concatenating * all the groups in oder, the resultant string should be 's'. given a string * 's', the size of each group 'k', and the character 'fill', return a string * array denoting the composition of every group 's' has been divided into. */ char **divideString(char *s, int k, char fill, int *returnSize) { int n = strlen(s), groups = (n + k - 1) / k; char **ans = (char **)malloc(groups * sizeof(char *)); *returnSize = groups; for (int i = 0; i < groups; i++) { ans[i] = (char *)malloc((k + 1) * sizeof(char)); for (int j = 0; j < k; j++) { int idx = i * k + j; ans[i][j] = idx < n ? s[idx] : fill; } ans[i][k] = '\0'; } return ans; } int main() { char *s1 = "abcdefghi", *s2 = "abcdefghij"; int rs1, rs2; char **ds1 = divideString(s1, 3, 'x', &rs1); char **ds2 = divideString(s2, 3, 'x', &rs2); for (int i = 0; i < rs1; i++) printf("%s ", ds1[i]); // expect: ["abc","def","ghi"] printf("\n"); for (int i = 0; i < rs2; i++) printf("%s ", ds2[i]); // expect: ["abc","def","ghi","jxx"] printf("\n"); for (int i = 0; i < rs1; i++) free(ds1[i]); for (int i = 0; i < rs2; i++) free(ds2[i]); }