Day 3

day3/Makefile

@@ -0,0 +1,10 @@
+solution-part%: solution-part%.c
+	gcc $< -o $@
+
+test-%: solution-% example.txt
+	$< example.txt
+
+run-%: solution-% realinput.txt
+	$< realinput.txt
+
+.PHONY: $(patsubst %,run-%, 1 2) $(patsubst %,test-%, 1 2)

day3/example.txt

@@ -0,0 +1,12 @@
+00100
+11110
+10110
+10111
+10101
+01111
+00111
+11100
+10000
+11001
+00010
+01010

day3/solution-part1.c

@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <string.h>
+
+
+int main( int argc, char *argv[] ){
+	if( argc == 2 ) {
+
+		unsigned int gamma = 0;
+		unsigned int epsilon = 0;
+		unsigned int lineLength = 0;
+		unsigned int noOfLines = 0;
+
+		// Read the values into an array
+		FILE *fp=fopen(argv[1], "r");
+		char ch = fgetc(fp);
+		while ( ch != '\n' ){
+			lineLength++;
+			ch = fgetc(fp);
+		}
+
+		rewind(fp);
+
+		unsigned int digitCount[lineLength];
+		memset( &digitCount, 0, lineLength*sizeof(unsigned int) );
+		
+
+		for ( int i = 0; !feof(fp); i++){
+			ch=fgetc(fp);
+			switch (ch) {
+				case '\n':
+					// I will be incremented at the end of the iteration
+					i=-1;
+					noOfLines++;
+					break;
+				case '1':
+					digitCount[i]++;
+					break;
+			}
+		}
+
+		for (unsigned int i=0; i < lineLength; i++ ){
+			if ( digitCount[i] > ( (double)noOfLines ) / 2 ){
+				gamma = gamma | 1 << (lineLength - i - 1);
+			} else {
+				epsilon = epsilon | 1 << (lineLength - i - 1);
+			}
+		}
+
+		printf("Answer: %d", gamma * epsilon);
+
+		return 0;
+	} else {
+		printf("You need to provide a file\n");
+		return 1;
+	}
+}

day3/solution-part1.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+
+file="$1"
+
+ones=(0 0 0 0 0 0 0 0 0 0 0 0)
+lines=0
+gamma=""
+epsilon=""
+
+while read line; do
+
+	bitn=0
+	while read bit; do
+		if [ "$bit" -eq 1 ]; then
+			ones[$bitn]=$((${ones[$bitn]} + 1))
+		fi
+		bitn=$(( bitn + 1 ))
+	done < <(echo "$line" | grep -o .)
+
+	lines="$((lines + 1))"
+
+done < <(cat "$file")
+
+echo "${ones[@]}"
+
+for i in ${ones[@]}; do
+	if [ "$i" -gt "$(( lines / 2 ))" ]; then
+		gamma="${gamma}1"
+		epsilon="${epsilon}0"
+	else
+		gamma="${gamma}0"
+		epsilon="${epsilon}1"
+	fi
+done
+
+
+gammaDecimal="$( echo "ibase=2; $gamma" | bc )"
+epsilonDecimal="$( echo "ibase=2; $epsilon" | bc )"
+
+echo "Gamma: $gamma -> $gammaDecimal"
+echo "Epsilon: $epsilon -> $epsilonDecimal"
+
+echo "Answer: $((gammaDecimal * epsilonDecimal))"

day3/solution-part2.c

@@ -0,0 +1,125 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+int countLines(char filename[]){
+	FILE *fp;
+	fp=fopen(filename, "r");
+	long int lines =0;
+
+	if ( fp == NULL ) {
+		return -1;
+	}
+
+	while (EOF != (fscanf(fp, "%*[^\n]"), fscanf(fp,"%*c")))
+		++lines;
+
+	fclose(fp); // closing file
+	return lines;
+}
+
+
+void countPositionBits(int linesize, int noOfLines, char *lines[noOfLines], unsigned int digitCount[]){
+	for ( int i = 0; i < noOfLines; i++){
+		for ( int j = 0; j < linesize; j++ ){
+			if ( lines[i][j] == '1' )
+				digitCount[j]++;
+		}
+	}
+}
+
+char* filterO2List(unsigned int linesize, unsigned int noOfLines, char **lines, unsigned int iteration){
+	if ( noOfLines == 1 )
+		return lines[0];
+
+	unsigned int digitCount[linesize];
+	memset( &digitCount, 0, linesize*sizeof(unsigned int) );
+	countPositionBits(linesize, noOfLines, lines, digitCount);
+
+	char bitKeep = ( digitCount[iteration] >= ((double)noOfLines) / 2 ) ? '1' : '0';
+
+	unsigned int newLinesIndex=0;
+	//Not sure why +4 here but any less and it buffer overflows
+	char **newLines = (char**)malloc((digitCount[iteration]+4) * sizeof(char*));
+
+	for ( unsigned int i=0; i < noOfLines; i++ ){
+		if (lines[i][iteration] == bitKeep)
+			newLines[newLinesIndex++] = lines[i];
+	}
+
+	return filterO2List( linesize, newLinesIndex, newLines, ++iteration );
+
+}
+
+char* filterCO2List(unsigned int linesize, unsigned int noOfLines, char **lines, unsigned int iteration){
+	if ( noOfLines == 1 )
+		return lines[0];
+
+	unsigned int digitCount[linesize];
+	memset( &digitCount, 0, linesize*sizeof(unsigned int) );
+	countPositionBits(linesize, noOfLines, lines, digitCount);
+
+	char bitKeep = ( digitCount[iteration] >= ((double)noOfLines) / 2 ) ? '0' : '1';
+
+	unsigned int newLinesIndex=0;
+	//Not sure why +4 here but any less and it buffer overflows
+	char **newLines = (char**)malloc((digitCount[iteration]+4) * sizeof(char*));
+
+	for ( unsigned int i=0; i < noOfLines; i++ ){
+		if (lines[i][iteration] == bitKeep)
+			newLines[newLinesIndex++] = lines[i];
+	}
+
+	return filterCO2List( linesize, newLinesIndex, newLines, ++iteration );
+
+}
+
+int main( int argc, char *argv[] ){
+	if( argc == 2 ) {
+
+		unsigned int gamma = 0;
+		unsigned int epsilon = 0;
+		unsigned int lineLength = 0;
+		unsigned int noOfLines = countLines( argv[1] );
+		unsigned int iteration=0;
+
+		// Read the values into an array
+		FILE *fp=fopen(argv[1], "r");
+		char ch = fgetc(fp);
+		while ( ch != '\n' ){
+			lineLength++;
+			ch = fgetc(fp);
+		}
+
+		rewind(fp);
+
+		unsigned int digitCount[lineLength];
+		memset( &digitCount, 0, lineLength*sizeof(int) );
+		
+		// Make a big array to hold the lines
+		char **lines = (char**)malloc(noOfLines * sizeof(char*));
+
+		// Loop through the file and populate the array
+		for ( unsigned int i = 0; !feof(fp); i++){
+
+			char *line = (char*)malloc(lineLength);
+			fscanf(fp, "%s\n", line);
+			lines[i] = line;
+		}
+
+		char *o2Rating = filterO2List( lineLength, noOfLines, lines, 0 );
+		char *co2Rating = filterCO2List( lineLength, noOfLines, lines, 0 );
+
+		int o2RatingDec = (int)strtol(o2Rating, NULL, 2);
+		int co2RatingDec = (int)strtol(co2Rating, NULL, 2);
+
+		printf("O2 Rating: %s -> %i\n", o2Rating, o2RatingDec);
+		printf("CO2 Rating: %s -> %i\n", co2Rating, co2RatingDec);
+		printf("Answer: %i\n", o2RatingDec * co2RatingDec);
+
+		return 0;
+	} else {
+		printf("You need to provide a file\n");
+		return 1;
+	}
+}

day3/solution-part2.sh

@@ -0,0 +1,108 @@
+#!/usr/bin/env bash
+
+file="$1"
+
+
+gamma=""
+epsilon=""
+
+countPositionBits(){
+	ones=(0 0 0 0 0 0 0 0 0 0 0 0)
+	#ones=(0 0 0 0 0)
+	stdin="$(cat -)"
+
+	while read line; do
+
+		bitn=0
+		while read bit; do
+			if [ "$bit" -eq 1 ]; then
+				ones[$bitn]=$((${ones[$bitn]} + 1))
+			fi
+			bitn=$(( bitn + 1 ))
+		done < <(echo "$line" | grep -o .)
+
+
+	done < <(echo "$stdin")
+
+	printf '%s\n' "${ones[@]}"
+
+}
+
+dots(){
+	seq $i | sed 's/.*/./' | tr -d '\n'
+}
+
+ogr="$(cat "$1")"
+csr="$(cat "$1")"
+
+echo "OGR"
+
+i=0
+while [ "$(echo "$ogr" | wc -l)" -gt 1 ]; do
+	counts="$(echo "$ogr" | countPositionBits)"
+	noofogr="$(echo "$ogr" | wc -l)"
+	noofones="$( echo "$counts" | sed -n "$((i + 1))p" )"
+	echo "$ogr"
+	echo "No of ones $noofones"
+	echo "No of ogr $noofogr"
+	if [ "$((noofones * 10))" -ge "$(( noofogr * 10 / 2 ))" ]; then
+		echo "Filtering only 1s in position $i"
+		echo "^$(dots $i)1"
+		ogr="$(echo "$ogr" | grep "^$(dots $i)1" )"
+	else
+		echo "Filtering only 0s in position $i"
+		ogr="$(echo "$ogr" | grep "^$(dots $i)0" )"
+	fi
+	echo -e "\n---\n"
+	i="$((i + 1))"
+done
+
+echo "CSR"
+
+i=0
+while [ "$(echo "$csr" | wc -l)" -gt 1 ]; do
+	counts="$(echo "$csr" | countPositionBits)"
+	noofcsr="$(echo "$csr" | wc -l)"
+	noofones="$( echo "$counts" | sed -n "$((i + 1))p" )"
+	echo "$csr"
+	echo "No of ones $noofones"
+	echo "No of csr $noofcsr"
+	if [ "$((noofones * 10))" -ge "$(( noofcsr * 10 / 2 ))" ]; then
+		echo "Filtering only 0s in position $i"
+		echo "^$(dots $i)1"
+		csr="$(echo "$csr" | grep "^$(dots $i)0" )"
+	else
+		echo "Filtering only 1s in position $i"
+		csr="$(echo "$csr" | grep "^$(dots $i)1" )"
+	fi
+	echo -e "\n---\n"
+	i="$((i + 1))"
+done
+
+
+ogrDecimal="$( echo "ibase=2; $ogr" | bc )"
+csrDecimal="$( echo "ibase=2; $csr" | bc )"
+
+echo "Oxxygen Generator Rating: $ogr -> $ogrDecimal"
+echo "CO2 Scrubber Rating: $csr -> $csrDecimal"
+
+echo "Answer: $((ogrDecimal * csrDecimal))"
+
+
+#while read i; do
+#	if [ "$i" -gt "$(( lines / 2 ))" ]; then
+#		gamma="${gamma}1"
+#		epsilon="${epsilon}0"
+#	else
+#		gamma="${gamma}0"
+#		epsilon="${epsilon}1"
+#	fi
+#done < <(echo "")
+#
+#gammaDecimal="$( echo "ibase=2; $gamma" | bc )"
+#epsilonDecimal="$( echo "ibase=2; $epsilon" | bc )"
+#
+#echo "Gamma: $gamma -> $gammaDecimal"
+#echo "Epsilon: $epsilon -> $epsilonDecimal"
+#
+#echo "Answer: $((gammaDecimal * epsilonDecimal))"