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#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
enum worry_op {
WO_NONE,
WO_ADD,
WO_MUL,
WO_SQR,
};
struct monkey {
int * items;
int nitems;
enum worry_op wo;
int wparam;
int test_div;
int test_true;
int test_false;
int inspections;
};
void
monkey_init(struct monkey * m)
{
m->items = NULL;
m->nitems = 0;
m->wo = WO_NONE;
m->wparam = 0;
m->test_div = 0;
m->test_true = 0;
m->test_false = 0;
m->inspections = 0;
}
void
monkey_dtor(struct monkey * m)
{
free(m->items);
}
int
monkey_isvalid(struct monkey const * m, int max)
{
return m->wo != WO_NONE
&& m->test_div != 0
&& m->test_true >= 0 && m->test_true < max
&& m->test_false >= 0 && m->test_false < max;
}
int
monkey_additem(struct monkey * m, int worry)
{
void * p;
++m->nitems;
p = realloc(m->items, m->nitems * sizeof(int));
if (!p)
return 0;
m->items = p;
m->items[m->nitems - 1] = worry;
return 1;
}
void
monkey_dump(struct monkey const * m, int n)
{
int * i;
fprintf(stderr, "Monkey %d: %d/%d/%d/%d/%d/%d: ",
n, m->wo, m->wparam, m->test_div, m->test_true, m->test_false, m->inspections);
for (i = m->items; i < m->items + m->nitems; ++i) {
fprintf(stderr, "%s%d", i == m->items ? "" : ", ", *i);
}
fprintf(stderr, "\n");
}
int
main()
{
char buf[BUFSIZ];
struct monkey * monkeys = NULL, * m = NULL;
int nmonkeys = 0;
int i, j;
// Read monkey data
while (fgets(buf, sizeof(buf), stdin)) {
if (buf[0] == '\n') {
// Ignore blank line
}
else if (strncmp(buf, "Monkey ", 7) == 0 && isdigit(buf[7])) {
void * p;
++nmonkeys;
if ((i = atoi(buf + 7)) != nmonkeys - 1) {
fprintf(stderr, "Bad monkey %d/%d!\n", i, nmonkeys);
free(monkeys);
return -1;
}
p = realloc(monkeys, nmonkeys * sizeof(struct monkey));
if (!p) {
fprintf(stderr, "realloc(%zd) fail\n", nmonkeys * sizeof(struct monkey));
free(monkeys);
return -1;
}
monkeys = p;
m = monkeys + nmonkeys - 1;
monkey_init(m);
}
else if (strncmp(buf, " Starting items: ", 18) == 0 && isdigit(buf[18])) {
char * cur, * next;
int worry;
cur = buf + 18;
worry = strtol(cur, &next, 10);
while (next != cur) {
monkey_additem(m, worry);
cur = next + 1;
worry = strtol(cur, &next, 10);
}
}
else if (strncmp(buf, " Operation: new = old ", 23) == 0) {
switch (buf[23]) {
case '+': m->wo = WO_ADD; break;
case '*': m->wo = WO_MUL; break;
default:
fprintf(stderr, "Unexpected op %c\n", buf[23]);
free(monkeys);
return -1;
}
if (strncmp(buf + 25, "old", 3) == 0 && m->wo == WO_MUL) {
m->wo = WO_SQR;
}
else {
m->wparam = atoi(buf + 25);
}
}
else if (strncmp(buf, " Test: divisible by ", 21) == 0 && isdigit(buf[21])) {
m->test_div = atoi(buf + 21);
}
else if (strncmp(buf, " If true: throw to monkey ", 29) == 0 && isdigit(buf[29])) {
m->test_true = atoi(buf + 29);
}
else if (strncmp(buf, " If false: throw to monkey ", 30) == 0 && isdigit(buf[30])) {
m->test_false = atoi(buf + 30);
}
else {
fprintf(stderr, "Unexpected monkey: %s\n", buf);
free(monkeys);
return -1;
}
}
// Check monkeys are valid
for (m = monkeys; m < monkeys + nmonkeys; ++m) {
#if 0
monkey_dump(m, m - monkeys);
#endif
if (!monkey_isvalid(m, nmonkeys)) {
fprintf(stderr, "Bad monkey %d\n", (int) (m - monkeys));
monkey_dump(m, m - monkeys);
free(monkeys);
return -1;
}
}
// Perform monkey inspection rounds
for (i = 0; i < 20; ++i) {
for (m = monkeys; m < monkeys + nmonkeys; ++m) {
int * item;
for (item = m->items; item < m->items + m->nitems; ++item) {
int catcher;
switch (m->wo) {
case WO_NONE: break; /* shouldn't happen */
case WO_ADD: *item += m->wparam; break;
case WO_MUL: *item *= m->wparam; break;
case WO_SQR: *item *= *item; break;
}
*item /= 3;
catcher = *item % m->test_div ? m->test_false : m->test_true;
monkey_additem(monkeys + catcher, *item);
++m->inspections;
}
m->nitems = 0;
}
#if 0
for (m = monkeys; m < monkeys + nmonkeys; ++m) {
monkey_dump(m, m - monkeys);
}
#endif
}
// Calculate monkey business
i = j = 0;
for (m = monkeys; m < monkeys + nmonkeys; ++m) {
if (m->inspections > i) {
j = i;
i = m->inspections;
}
else if (m->inspections > j) {
j = m->inspections;
}
}
printf("Monkey business: %d (%d * %d)\n", i * j, i, j);
// Done.
for (m = monkeys; m < monkeys + nmonkeys; ++m) {
monkey_dtor(m);
}
free(monkeys);
return 0;
}
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