100 lines
2.2 KiB
C
100 lines
2.2 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <stdbool.h>
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#define DEFAULT_FILE "input.txt"
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#define STRBUF_LEN 200
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#define WINNING_NUM_SIZE 10
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#define HOLDING_NUM_SIZE 25
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#define ISDIGIT(X) (X >= '0' && X <= '9')
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void parse_nums(char *str, uint8_t *nums, uint8_t len)
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{
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uint8_t i = 0;
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uint8_t digit_idx = 0;
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char c;
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uint8_t num = 0;
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for (i = 0; i < len; i++)
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{
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num = 0;
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digit_idx = (i * 3);
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c = str[digit_idx];
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if (ISDIGIT(c)) num = (c - '0') * 10;
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num += str[digit_idx + 1] - '0';
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nums[i] = num;
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}
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}
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void parse_line(char *str, uint8_t *winning_nums, uint8_t *holding_nums)
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{
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while (*str != ':') str++;
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str += 2;
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parse_nums(str, winning_nums, WINNING_NUM_SIZE);
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while (*str != '|') str++;
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str += 2;
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parse_nums(str, holding_nums, HOLDING_NUM_SIZE);
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}
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bool num_in_set(uint8_t num, uint8_t *set, uint8_t len)
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{
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uint8_t i = 0;
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for (i = 0; i < len; i++)
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{
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if (num == set[i]) return true;
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}
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return false;
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}
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uint32_t calculate_points(uint8_t *winning_nums, uint8_t *holding_nums)
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{
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uint32_t points = 0;
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uint8_t i = 0;
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for (i = 0; i < HOLDING_NUM_SIZE; i++)
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{
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if (num_in_set(holding_nums[i], winning_nums, WINNING_NUM_SIZE)) {
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if (points) points = points * 2;
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else points = 1;
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}
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}
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return points;
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}
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int main(int argc, char **argv)
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{
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// Get filename as an argument, defaults to "input.txt"
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char *path = (argc > 1) ? argv[1] : DEFAULT_FILE;
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if (!path)
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{
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printf("Requires input file.\n");
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return 1;
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}
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FILE *file = fopen(path, "r");
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if (!file)
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{
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printf("Could not find file.");
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return 1;
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}
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char strbuf[STRBUF_LEN] = {0};
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uint8_t winning_nums[WINNING_NUM_SIZE] = {0};
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uint8_t holding_nums[HOLDING_NUM_SIZE] = {0};
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uint32_t totalpoints = 0;
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while (fgets(strbuf, STRBUF_LEN, file))
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{
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if (strbuf[0] == '\n') break;
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parse_line(strbuf, winning_nums, holding_nums);
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totalpoints += calculate_points(winning_nums, holding_nums);
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}
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printf("Total Points: %d\n", totalpoints);
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return 0;
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} |