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Overview
Comment:202407 1st star
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SHA3-256: 965ad94c163872620478dc5c7cefa2ce985beb7b602c60e32894b3275f703b12
User & Date: nnz on 2024-12-07 09:40:21
Other Links: manifest | tags
Context
2024-12-07
10:39
202407 2nd star check-in: 5a3d05d86e user: nnz tags: trunk
09:40
202407 1st star check-in: 965ad94c16 user: nnz tags: trunk
09:35
202407 -- answer too low, maybe got some overflowing check-in: 5cddab1bb6 user: nnz tags: trunk
Changes
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Modified aoc2024.c from [ef2e69e998] to [e5aa25e91a]. 

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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 v, unsigned *a, size_t n) {
    // for startes let's assume no overflowing
    if (n == 1) return (v == *a);
    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 calibrationtotal = 0;
    char *line = strtok(data, "\n");
    unsigned number[50], nnumber, maxn = 0;
    while (line) {
        char *err;
        unsigned testvalue = strtoul(line, &err, 10);
        err += 1; // skip ':'
        nnumber = 0;
        while (*err == ' ') {
            number[nnumber++] = strtoul(err, &err, 10);
        }
        if (canbetrue(testvalue, number, nnumber)) calibrationtotal += testvalue;
        if (nnumber > maxn) { maxn = nnumber; printf("max: %u\n", maxn); }
        line = strtok(NULL, "\n");
    }
    printf("The calibration total is {%u}.\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 bool canbetrue(unsigned long long v, unsigned long long *a, size_t n) {
    // for startes let's assume no overflowing
    if (n == 1) return (v == *a);
    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,
︙︙