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#include <ctype.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "aocutils.h"
void aoc202403(char *data, size_t len) {
(void)len; // unused argument
int sumproducts = 0, sumproducts2 = 0, term[2];
unsigned sumproducts = 0, sumproducts2 = 0, term[2];
char *rest = data;
char *doleft = data;
char *dorite = strstr(data + 1, "do()");
char *dontleft = data;
char *dontrite = strstr(dontleft + 1, "don't()");
for (;;) {
char *mul = strstr(rest, "mul(");
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while (dontrite && (mul > dontrite)) {
dontleft = dontrite;
dontrite = strstr(dontrite + 1, "don't()");
}
rest = mul + 4;
if (isdigit((unsigned char)rest[0])) {
char *err;
term[0] = strtol(rest, &err, 10);
term[0] = strtoul(rest, &err, 10);
if (*err == ',') {
if (isdigit((unsigned char)err[1])) {
rest = err + 1;
term[1] = strtol(rest, &err, 10);
term[1] = strtoul(rest, &err, 10);
if (*err == ')') {
sumproducts += term[0] * term[1];
// multiply by 0 if closest conditional to the left is "don't()"
sumproducts2 += (doleft >= dontleft) * (term[0] * term[1]);
rest = err + 1;
}
}
}
}
} else {
break;
}
}
printf("The sum of the products is {%d}.\n", sumproducts);
printf("The sum of the products with conditionals is {%d}.\n", sumproducts2);
printf("The sum of the products is {%u}.\n", sumproducts);
printf("The sum of the products with conditionals is {%u}.\n", sumproducts2);
}
static int safereport(int *v, int nv) {
static bool safereport(unsigned *v, size_t nv) {
int dir = 1; // ascending
if (v[0] > v[1]) dir = -1; // descending
for (int k = 1; k < nv; k++) {
if (v[k-1] == v[k]) return 0;
if (abs(v[k-1] - v[k]) > 3) return 0;
for (size_t k = 1; k < nv; k++) {
if (v[k-1] == v[k]) return false;
if (distance(v[k-1], v[k]) > 3) return false;
if (dir == -1) {
if (v[k-1] < v[k]) return 0;
if (v[k-1] < v[k]) return false;
} else {
if (v[k-1] > v[k]) return 0;
if (v[k-1] > v[k]) return false;
}
}
return 1;
return true;
}
static int safereportdamp(int *v, int nv) {
for (int swap = 0; swap < nv; swap++) { // abcde
int tmp = v[swap]; // swap(0, 0): a-bcde
v[swap] = v[0]; // swap(1, 0): b-acde
v[0] = tmp; // swap(2, 0): c-abde
if (safereport(v + 1, nv - 1)) return 1; // swap(3, 0): d-abce
} // ... and so on
return 0;
static bool safereportdamp(unsigned *v, size_t nv) {
for (size_t swap = 0; swap < nv; swap++) { // abcd...wx
unsigned tmp = v[swap]; // swap(0, 0): abcd...wx
v[swap] = v[0]; // swap(1, 0): bacd...wx
v[0] = tmp; // swap(2, 0): cabd...wx
if (safereport(v + 1, nv - 1)) return true; // ... and so on ...
} // swap(n-1, 0): xabc...vw
return false;
}
void aoc202402(char *data, size_t len) {
(void)len; // unused argument
int safe = 0, safe2 = 0;
unsigned safe = 0, safe2 = 0;
char *line = strtok(data, "\n");
while (line) {
int *arr = NULL;
int narr = text2array(&arr, line);
unsigned *arr = NULL;
size_t narr = text2array(&arr, line);
if (safereport(arr, narr)) {
safe += 1;
safe2 += 1;
} else {
safe2 += safereportdamp(arr, narr);
safe2 += safereportdamp(arr, narr) ? 1 : 0;
}
free(arr);
line = strtok(NULL, "\n");
}
printf("There are %d safe reports.\n", safe);
printf("There are %d safe reports with the Problem Dampener.\n", safe2);
printf("There are %u safe reports.\n", safe);
printf("There are %u safe reports with the Problem Dampener.\n", safe2);
}
static int delta(const void *a, const void *b) {
const unsigned *aa = a;
const unsigned *bb = b;
if (*aa > *bb) return 1;
if (*aa < *bb) return -1;
return *(const int *)a - *(const int *)b;
return 0;
}
#ifdef LISTSIZE
# error LISTSIZE already defined
#endif
#define LISTSIZE 1200
void aoc202401(char *data, size_t len) {
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for (size_t k = 0; k < n1; k++) {
#if 1 // use the fact lists are sorted: complexity: O(n log n)
unsigned leftcount = 1; // number of equal values in list1
while ((k + leftcount < n1) && (list1[k] == list1[k + leftcount])) leftcount++;
// find list1 k'ths value in list2
unsigned *p = bsearch(list1 + k, list2, n2, sizeof *list2, delta);
if (p) {
int idxl = p - list2; // search backwards and forwards in list2
int idxr = p - list2; // for the k'th value in list1
ptrdiff_t idxl = p - list2; // search backwards and forwards in list2
ptrdiff_t idxr = p - list2; // for the k'th value in list1
while ((idxl > 0) && (list2[idxl - 1] == *p)) idxl -= 1;
while ((idxr < (int)n2 - 1) && (list2[idxr + 1] == *p)) idxr += 1;
unsigned rightcount = (unsigned)(idxr - idxl + 1); // number of repeats in list2
unsigned rightcount = idxr - idxl + 1; // number of repeats in list2
similarity += *p * rightcount * leftcount;
}
k += leftcount - 1; // adjust loop control variable
#else
// loop inside loop: complexity O(n^2); don't care lists are sorted
unsigned count = 0;
for (size_t kk = 0; kk < n2; kk++) {
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