129 lines
2.6 KiB
C
129 lines
2.6 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <limits.h>
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#include "day.h"
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#define DATA_MAX_LEN 2048
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int parse_long_from_buff(char * buffer, int64_t * val) {
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*val = strtol(buffer, NULL, 16);
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if (*val == LONG_MIN || *val == LONG_MAX) {
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return -2;
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}
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return 0;
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}
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int read_input(const char * file_path, int64_t *data, uint16_t max_len) {
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char buffer[64];
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int c;
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int ret = 0;
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FILE * file = fopen(file_path, "r");
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int data_ndx = 0;
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if (file != NULL) {
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int buffer_ndx = 0;
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while ((c = fgetc(file)) != EOF) {
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if (c == '\n') {
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buffer[buffer_ndx] = 0;
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ret = parse_long_from_buff(buffer, &data[data_ndx]);
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if (ret < 0) {
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break;
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}
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data_ndx++;
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if (data_ndx >= max_len) {
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ret = -3;
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break;
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}
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buffer_ndx = 0;
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}
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else {
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buffer[buffer_ndx] = (char)c;
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buffer_ndx++;
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}
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}
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if (buffer_ndx > 0) {
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ret = parse_long_from_buff(buffer, &data[data_ndx]);
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if (ret == 0) {
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data_ndx++;
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}
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}
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}
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else {
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ret = -1;
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}
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if (ret == 0) {
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ret = data_ndx;
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}
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if (file != NULL) {
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fclose(file);
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}
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return ret;
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}
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void part_1(const int64_t * data, uint16_t data_len) {
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int64_t last_value;
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int16_t inc_count = 0;
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last_value = data[0];
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for (uint16_t i = 1; i < (uint16_t)data_len; i++) {
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if (data[i] > last_value) {
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inc_count++;
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}
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last_value = data[i];
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}
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printf("PART 1: %d values increased!\n", inc_count);
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}
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void part_2(const int64_t * data, uint16_t data_len) {
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int64_t old_window_sum;
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int64_t window_sum;
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int16_t inc_count = 0;
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old_window_sum = data[0] + data[1] + data[2];
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for (uint16_t i = 3; i < (uint16_t)data_len; i++) {
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window_sum = old_window_sum - data[i-3] + data[i];
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if (window_sum > old_window_sum) {
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inc_count++;
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}
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old_window_sum = window_sum;
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}
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printf("PART 2: %d windows increased!\n", inc_count);
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}
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int day_1() {
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char * path = "../inputs/day_1.txt";
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int data_len;
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int64_t data[DATA_MAX_LEN];
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data_len = read_input(path, data, DATA_MAX_LEN);
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if (data_len < 0) {
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printf("read_input returned an error: %d\n", data_len);
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return data_len;
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}
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part_1(data, data_len);
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part_2(data, data_len);
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return 0;
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} |