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#include <ctype.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "aocdailies.h"
#include "aocutils.h"
/* === aoc202407 =======================================================
Part one looks easy
===================================================================== */
static unsigned long long concat(unsigned long long a, unsigned long long b) {
unsigned long long r = a, t = b;
while (b) {
r *= 10;
b /= 10;
}
return r + t;
}
static bool canbetrue(unsigned long long v, unsigned long long *a, size_t n) {
if (n == 1) return (v == *a);
unsigned long long tmp = a[1];
a[1] = a[0] + tmp;
if (canbetrue(v, a+1, n-1)) { a[1] = tmp; return true; }
a[1] = a[0] * tmp;
if (canbetrue(v, a+1, n-1)) { a[1] = tmp; return true; }
a[1] = tmp;
return false;
}
static bool canbetrue3(unsigned long long v, unsigned long long *a, size_t n) {
// still, let's assume no unsigned long long overflowing
if (n == 1) return (v == *a);
unsigned long long tmp = a[1];
a[1] = a[0] + tmp;
if (canbetrue3(v, a+1, n-1)) { a[1] = tmp; return true; }
a[1] = a[0] * tmp;
if (canbetrue3(v, a+1, n-1)) { a[1] = tmp; return true; }
a[1] = concat(a[0], tmp);
if (canbetrue3(v, a+1, n-1)) { a[1] = tmp; return true; }
a[1] = tmp;
return false;
}
void aoc202407(char *data, size_t len) {
(void)len; // unused argument
unsigned long long calibrationtotal = 0, calibration3total = 0;
char *line = strtok(data, "\n");
unsigned long long number[50], nnumber;
while (line) {
char *err;
unsigned long long testvalue = strtoull(line, &err, 10);
err += 1; // skip ':'
nnumber = 0;
while (*err == ' ') {
number[nnumber++] = strtoul(err, &err, 10);
}
if (canbetrue(testvalue, number, nnumber)) {
calibrationtotal += testvalue;
}
if (canbetrue3(testvalue, number, nnumber)) {
calibration3total += testvalue;
}
line = strtok(NULL, "\n");
}
printf("The calibration total is {%llu}.\n", calibrationtotal);
printf("The calibration total with three operators is {%llu}.\n", calibration3total);
}
/* === aoc202406 =======================================================
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#include <ctype.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "aocdailies.h"
#include "aocutils.h"
/* === aoc202407 =======================================================
Part one looks easy
Part two also easy
===================================================================== */
static unsigned long long concat(unsigned long long a, unsigned long long b) {
unsigned long long r = a, t = b;
while (b) {
r *= 10;
b /= 10;
}
return r + t;
}
static int operatorsrequired(unsigned long long v, unsigned long long *a, size_t n, int minop) {
// assumes no unsigned long long overflowing
if (n == 1) {
if (v == *a) return minop;
return 0;
}
unsigned long long tmp = a[1];
a[1] = a[0] + tmp;
int p = operatorsrequired(v, a+1, n-1, (minop > 2)?3:2);
a[1] = tmp;
if (p) return p;
a[1] = a[0] * tmp;
p = operatorsrequired(v, a+1, n-1, (minop > 2)?3:2);
a[1] = tmp;
if (p) return p;
a[1] = concat(a[0], tmp);
p = operatorsrequired(v, a+1, n-1, 3);
a[1] = tmp;
return p;
}
void aoc202407(char *data, size_t len) {
(void)len; // unused argument
unsigned long long calibrationtotal = 0, calibration3total = 0;
char *line = strtok(data, "\n");
unsigned long long number[50], nnumber;
while (line) {
char *err;
unsigned long long testvalue = strtoull(line, &err, 10);
err += 1; // skip ':'
nnumber = 0;
while (*err == ' ') {
number[nnumber++] = strtoul(err, &err, 10);
}
switch (operatorsrequired(testvalue, number, nnumber, 0)) {
default: break;
case 2: calibrationtotal += testvalue;
__attribute__((fallthrough));
case 3: calibration3total += testvalue;
break;
}
#if 0
if (canbetrue(testvalue, number, nnumber)) {
calibrationtotal += testvalue;
}
if (canbetrue3(testvalue, number, nnumber)) {
calibration3total += testvalue;
}
#endif
line = strtok(NULL, "\n");
}
printf("The calibration total is {%llu}.\n", calibrationtotal);
printf("The calibration total with three operators is {%llu}.\n", calibration3total);
}
/* === aoc202406 =======================================================
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data[linearize2d(size, (unsigned)row_pos, (unsigned)col_pos)] = 'X'; // initial place visited
while (validpos(size, row_pos + deltarow, col_pos + deltacol)) {
switch (data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))]) {
default: exit(EXIT_FAILURE); // does not happen
case '#': rightturn(&deltarow, &deltacol); break;
case '.': visited++;
data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))] = 'X';
/*fallthrough*/
case 'X': row_pos += deltarow;
col_pos += deltacol;
break;
}
}
printf("The guard visits %u positions before leaving the area.\n", visited);
// Part Two
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data[linearize2d(size, (unsigned)row_pos, (unsigned)col_pos)] = 'X'; // initial place visited
while (validpos(size, row_pos + deltarow, col_pos + deltacol)) {
switch (data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))]) {
default: exit(EXIT_FAILURE); // does not happen
case '#': rightturn(&deltarow, &deltacol); break;
case '.': visited++;
data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))] = 'X';
__attribute__((fallthrough));
case 'X': row_pos += deltarow;
col_pos += deltacol;
break;
}
}
printf("The guard visits %u positions before leaving the area.\n", visited);
// Part Two
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switch (data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))]) {
default: puts("stepped on default"); exit(EXIT_FAILURE);
case '#': if (data[linearize2d(size, (unsigned)(row_pos), (unsigned)(col_pos))] == '4') looping = true;
rightturn(&deltarow, &deltacol);
break;
case '4': looping = true; break;
case '.': data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))] = '0';
/*fallthrough*/
case '1':
case '2':
case '3': data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))]++;
row_pos += deltarow;
col_pos += deltacol;
break;
}
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switch (data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))]) {
default: puts("stepped on default"); exit(EXIT_FAILURE);
case '#': if (data[linearize2d(size, (unsigned)(row_pos), (unsigned)(col_pos))] == '4') looping = true;
rightturn(&deltarow, &deltacol);
break;
case '4': looping = true; break;
case '.': data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))] = '0';
__attribute__((fallthrough));
case '1':
case '2':
case '3': data[linearize2d(size, (unsigned)(row_pos+deltarow), (unsigned)(col_pos+deltacol))]++;
row_pos += deltarow;
col_pos += deltacol;
break;
}
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