advent-of-code/05/day5.c
2019-09-24 16:52:43 +02:00

47 lines
1.0 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
int isSameLetter(char a, char b) {
char diff = (a > b) ? a - b : b - a;
return diff == 32;
}
int processArray(char* input, int length) {
int outputLength = 0;
for (int i=0; i<length; i++) {
if (isSameLetter(input[i], input[i+1]) == 1) {
i++;
} else {
input[outputLength] = input[i];
outputLength++;
}
}
return outputLength;
}
int main() {
struct stat stbuffer;
FILE *inputFile = fopen("input", "r");
fstat(fileno(inputFile), &stbuffer);
int inSize = stbuffer.st_size + 1;
//inSize = 20;
//fseek(inputFile, 10020, 0);
char *input = malloc(inSize);
fgets(input, inSize, inputFile);
int lastLength = inSize;
int outLength = inSize;
do {
lastLength = outLength;
outLength = processArray(input, lastLength);
} while (lastLength != outLength);
printf("%d\n", outLength - 1);
fclose(inputFile);
free(input);
return 0;
}