C语言基础-C语言编程基础之Leetcode编程题解之第38题外观数列.zip

#include <stdio.h> #include <stdlib.h> #include <string.h> static void parse(char *input, char *output) { char *p = input; char *q = output; while (*p != '\0') { int count = 1; while (p[0] == p[1]) { count++; p++; } /* reverse number */ int n = 0; while (count > 0) { n += count % 10; count /= 10; } /* parse count */ while (n > 0) { *q++ = (n % 10) + '0'; n /= 10; } *q++ = p[0]; p++; } *q = '\0'; } static char *countAndSay(int n) { if (n < 1) { return NULL; } char *result; char *prev = malloc(10000); char *next = malloc(10000); strcpy(prev, "1"); if (n == 1) { return prev; } int i; for (i = 2; i <= n; i++) { if (i & 0x1) { parse(next, prev); result = prev; } else { parse(prev, next); result = next; } } return result; } int main(int argc, char **argv) { if (argc != 2) { fprintf(stderr, "Usage: ./test n\n"); exit(-1); } printf("%s\n", countAndSay(atoi(argv[1]))); return 0; }