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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 bool canbetrue(unsigned long long v, unsigned long long *a, size_t n) {
// for startes let's assume no overflowing
unsigned tmp = a[1];
a[1] = a[0] + tmp;
if (canbetrue(v, a+1, n-1)) return true;
a[1] = a[0] * tmp;
if (canbetrue(v, a+1, n-1)) return true;
a[1] = tmp;
return false;
}
void aoc202407(char *data, size_t len) {
(void)len; // unused argument
unsigned long long calibrationtotal = 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;
line = strtok(NULL, "\n");
}
printf("The calibration total is {%llu}.\n", calibrationtotal);
}
/* === aoc202406 =======================================================
Hmmm, I've done something like this already this year... on day 4
I need rcmap() moved to aocutils ... done; now it's called `linearize2d`
Part Two: brute force? It likely is faster than coming up with an algo
Let's go: save map, for every available position put in an obstacle,
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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 =======================================================
Hmmm, I've done something like this already this year... on day 4
I need rcmap() moved to aocutils ... done; now it's called `linearize2d`
Part Two: brute force? It likely is faster than coming up with an algo
Let's go: save map, for every available position put in an obstacle,
|