Playing with http://thecodersbreakfast.net/index.php?post/2013/02/18/Coding-challenge-maman-les-petits-avions

syr.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

const char *g_progname;
const char *g_name;

struct seq {
  int *vals;
  int size;
  int alloc;
};

#define SEQ_PUSH(_SEQ, _VAL) do {                                                \
  if ((_SEQ)->size >= (_SEQ)->alloc) {                                           \
    (_SEQ)->alloc = 2 * (_SEQ)->alloc;                                           \
    (_SEQ)->vals = realloc((_SEQ)->vals, (_SEQ)->alloc * sizeof(int));           \
  }                                                                              \
  (_SEQ)->vals[(_SEQ)->size++] = (_VAL);                                         \
} while (0);

#define SEQ_TAIL(_SEQ) (_SEQ)->vals[(_SEQ)->size - 1]

static int tonum(const char *name);
static struct seq *toseq(int num);
static int alt_flight_time(const struct seq *s);
static int alt_max(const struct seq *s);

int main(int argc, char **argv) {
  g_progname = argv[0];
  if (argc != 2) {
    fprintf(stderr, "usage: %s name\n", g_progname);
    exit(1);
  }
  g_name = argv[1];
  struct seq *s = toseq(tonum(g_name));
  printf("%s:\n", g_name);
  printf("  temps de vol: %d\n", s->size);
  printf("  temps de vol en altitude: %d\n", alt_flight_time(s));
  printf("  altitude max: %d\n", alt_max(s));
  free(s->vals);
  free(s);
  return 0;
}

static int tonum(const char *name) {
  int num = 0;
  while (*name != '\0') num += *(name++);
  return num;
}

static struct seq *toseq(int num) {
  struct seq *s = malloc(sizeof(*s));
  s->vals = malloc(32*sizeof(int));
  s->alloc = 32;
  s->size = 0;
  SEQ_PUSH(s, num);
  for (;;) {
    num = SEQ_TAIL(s);
    if (num <= 1) break;
    SEQ_PUSH(s, num % 2 ? ((num * 3 ) + 1) : (num >> 1));
  }
  return s;
}

static int alt_max(const struct seq *s) {
  int i, max = s->vals[0];
  for (i = 1; i < s->size; i++) {
    if (s->vals[i] > max) max = s->vals[i];
  }
  return max;
}

static int alt_flight_time(const struct seq *s) {
  int i, time = 1;
  for (i = 1; i < s->size; i++) {
    if (s->vals[i] >= s->vals[0]) time++;
    else break;
  }
  return time;
}