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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if 0
#define PART part1
#else
#define PART part2
#endif
#if 0
#define FILENAME "sample.txt"
#else
#define FILENAME "input.txt"
#endif
int sum = 0;
int char_to_index(char ch)
{
if(ch >= 'a')
return ch - 'a';
return ch - 'A' + 26;
}
void part1(char *line)
{
int times_seen[56] = {0};
int leftest[56] = {0}; // rightest position of that character seen
int rightest[56] = {0}; // leftest position of that character seen
int len = strlen(line);
len = (len % 2) ? len : len - 1; // fgets reads the new line and the last line has no newline
for(int i = 0; i < len; i++)
{
int ch = char_to_index(line[i]);
times_seen[ch]++;
if(times_seen[ch] == 1)
leftest[ch] = i;
else
rightest[ch] = i;
if(times_seen[ch] > 1)
if(leftest[ch] < len/2 && rightest[ch] >= len/2) {
sum += ch + 1;
break;
}
}
}
int gn = 0;
int times_seen[56][3] = {0};
void part2(char *line)
{
for(int i = 0; line[i] != '\n' && line[i] != '\0'; i++)
times_seen[char_to_index(line[i])][gn]++;
gn++;
if(gn == 3) {
for(int j = 0; j < 56; j++)
if(times_seen[j][0] && times_seen[j][1] && times_seen[j][2]) {
sum += j + 1;
break;
}
gn = 0;
memset(times_seen, 0, sizeof(times_seen));
}
}
void parse()
{
FILE *fp = fopen(FILENAME, "r");
if(!fp) {
fprintf(stderr, "ERROR: Could not open file: %s\n", FILENAME);
exit(1);
}
char line[256];
while(fgets(line, sizeof(line), fp) != NULL)
PART(line);
fclose(fp);
}
int main(void)
{
parse();
printf("%d\n", sum);
return 0;
}
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