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Check-in [9237d89a9a]

Overview
Comment:reworked operators insertion logic
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Files: files | file ages | folders
SHA3-256: 9237d89a9aa66ba1e499075f64d60789604a5be951a0ba08ea7b172cd25e045d
User & Date: nnz on 2024-12-07 13:50:22
Other Links: manifest | tags
Context
2024-12-07
13:52
removed dead code check-in: 278fc62fcc user: nnz tags: trunk
13:50
reworked operators insertion logic check-in: 9237d89a9a user: nnz tags: trunk
10:39
202407 2nd star check-in: 5a3d05d86e user: nnz tags: trunk
Changes
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Modified aoc2024.c from [d3378fca96] to [98d4a70597]. 

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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 bool canbetrue(unsigned long long v, unsigned long long *a, size_t n) {
    if (n == 1) return (v == *a);
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;
    if (canbetrue(v, a+1, n-1)) { a[1] = tmp; return true; }
    int p = operatorsrequired(v, a+1, n-1, (minop > 2)?3:2);
    a[1] = a[0] * tmp;
    if (canbetrue(v, a+1, n-1)) { a[1] = tmp; return true; }
    a[1] = tmp;
    return false;
    if (p) return p;
}

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] = 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);
    if (canbetrue3(v, a+1, n-1)) { a[1] = tmp; return true; }
    p = operatorsrequired(v, a+1, n-1, 3);
    a[1] = tmp;
    return false;
    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*/
                      __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*/
                              __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;
                }
︙