solved day 1 and 2

1/inputDemo

@@ -0,0 +1,6 @@
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3

1/main.c

@@ -0,0 +1,49 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#define LINES 1000
+
+int compare(const void *a, const void *b);
+
+int main()
+{
+	// populate arrays from file
+	FILE *input;
+	input = fopen("./input", "r");
+	unsigned int left[LINES];
+	unsigned int right[LINES];
+
+	for (int i = 0; i < LINES; i++) {
+		fscanf(input, "%d", &left[i]);
+		// printf("%d left: %d	", i, left[i]);
+		fscanf(input, "%d", &right[i]);
+		// printf("%d right: %d\n", i, right[i]);
+	}
+
+	// sort arrays
+	qsort(left, LINES, sizeof(int), compare);
+	qsort(right, LINES, sizeof(int), compare);
+	/*
+	for (int i = 0; i < LINES; i++) {
+		printf("%d left: %d	", i, left[i]);
+		printf("%d right: %d\n", i, right[i]);
+	}
+	*/
+
+	// compare each element n, add its difference to sum-var
+	unsigned long int distance = 0;
+	for (int i = 0; i < LINES; i++) {
+		distance += abs(left[i] - right[i]);
+	}
+	printf("distance: %d\n", distance);
+}
+
+int compare(const void *a, const void *b)
+{
+	int int_a = * ((int*) a);
+	int int_b = * ((int*) b);
+	
+	if (int_a == int_b) return 0;
+	else if (int_a < int_b) return -1;
+	else return 1;
+}

1/mainB.c

@@ -0,0 +1,51 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#define LINES 1000
+
+int compare(const void *a, const void *b);
+
+int main()
+{
+	// populate arrays from file
+	FILE *input;
+	input = fopen("./input", "r");
+	unsigned int left[LINES];
+	unsigned int right[LINES];
+
+	for (int i = 0; i < LINES; i++) {
+		fscanf(input, "%d", &left[i]);
+		// printf("%d left: %d	", i, left[i]);
+		fscanf(input, "%d", &right[i]);
+		// printf("%d right: %d\n", i, right[i]);
+	}
+	/*
+	for (int i = 0; i < LINES; i++) {
+		printf("%d left: %d	", i, left[i]);
+		printf("%d right: %d\n", i, right[i]);
+	}
+	*/
+
+	// check how many times left[i] is in right[]. multiply left[i] by this.
+	// then sum it
+	unsigned long int sum = 0;
+	for (int i = 0; i < LINES; i++) {
+		int numRight = 0;
+		for (int j = 0; j < LINES; j++) {
+			numRight += left[i] == right[j];
+		}
+		sum += left[i] * numRight;
+	}
+	
+	printf("sum: %d\n", sum);
+}
+
+int compare(const void *a, const void *b)
+{
+	int int_a = * ((int*) a);
+	int int_b = * ((int*) b);
+	
+	if (int_a == int_b) return 0;
+	else if (int_a < int_b) return -1;
+	else return 1;
+}

2/'

@@ -0,0 +1,86 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#define LINES 1000
+
+// power! x to the y!
+int pow(int x, int y)
+{
+	int ans = 1;
+	for (int i = 0; i < y; i++) ans *= x;
+	return ans;
+}
+// parse string into array of numbers
+int parse_numbers(char *str_row, int *row, int n)
+{
+	int i = 0;
+	for (; str_row[i] != '\n'; i++);
+	for (; i >= 0; i--) {
+		int pos = 0;
+		for (; str_row[i] >= '0' && str_row[i] <= '9' && i >= 0; i--) {
+			row[n] += (str_row[i] - '0') * pow(10, pos);
+			pos++;
+		}
+		n--;
+	}
+
+	return 1;
+}
+// check if specific report is safe
+int check_report(int *row, int len)
+{
+	// read number. Compare next number (higher, lower, +-1-2)
+	// if you get to row[i + 1]line, ++
+	int rising = 0;
+	int first = 1;
+	for (int i = 0; i < len - 1; i++) {
+		// if difference isnt 1-3
+		if (abs(row[i + 1] - row[i]) > 3 || abs(row[i + 1] - row[i]) < 1)
+			return 0;
+		// only for first comparison of row. Set direction.
+		if (first && ((row[i + 1] - row[i]) < 0))
+			rising = 0;
+		else if (first)
+			rising = 1;
+		// for other comparisons, compare current direction to the previous.
+		if (!first && (rising != !((row[i + 1] - row[i]) < 0))) {
+			// printf("rising: %d while %d - %d is %d\n", rising, row[i + 1], row[i], row[i + 1] - row[i]);
+			return 0;
+		}
+		// get ready for the next comparisons!
+		first = 0;
+	}
+	return 1;
+}
+
+int dampener(int *row, int len)
+{
+	if (check_report(row, len)) return 1;
+}
+
+int main()
+{
+	int safe = 0;
+	// read input row into array, count elements
+	FILE *input;
+	input = fopen("./input", "r");
+	char line[32];
+	for (int i = 0; i < LINES; i++) {
+		// get string (line), count numbers, put into int array (row)
+		int numbers = 1;
+		fgets(line, sizeof(line), input);
+		// count number of numbers, allocate memory
+		for (int c = 0; line[c]; c++) numbers += (line[c] == ' ');
+		int *row = (int *)calloc(numbers, sizeof(int));
+		// parse numbers into array
+		parse_numbers(line, row, numbers);
+		// for (int j = 0; j < numbers; j++) printf("%d ", row[j]);
+		// printf("\n\n");
+
+		// send elements and length to check_report, add result to sum
+		safe += check_report(row, numbers);
+		free(row);
+	}
+
+	printf("%d\n", safe);
+}

2/inputDemo

@@ -0,0 +1,6 @@
+7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9

2/main.c

@@ -0,0 +1,45 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#define LINES 1000
+
+int compare(const void *a, const void *b);
+
+int main()
+{
+	int new;
+	int old;
+	int safe = 0;
+	FILE *input;
+	input = fopen("./input", "r");
+	// read number. Compare next number (higher, lower, +-1-2)
+	// if you get to newline, ++
+	for (int i = 0; i < LINES; i++) {
+		int rising = 0;
+		int first = 1;
+		fscanf(input, "%d", &old);
+		char nextChar = 0;
+		while ((nextChar = fgetc(input)) && nextChar != '\n') {
+			fscanf(input, "%d", &new);
+			// if difference isnt 1-3
+			if (abs(new - old) > 3 || abs(new - old) < 1) {
+				while(getc(input) != '\n');
+				goto loopEnd;
+			}
+			// only for first comparison of row. Set direction.
+			if (first && ((new - old) < 0)) rising = 0; else if (first) rising = 1;
+			// for other comparisons, compare current direction to the previous.
+			if (!first && (rising != !((new - old) < 0))) {
+				// printf("rising: %d while %d - %d is %d\n", rising, new, old, new - old);
+				while(getc(input) != '\n');
+				goto loopEnd;
+			}
+			// get ready for the next comparisons!
+			first = 0;
+			old = new;
+		}
+		safe++;
+		loopEnd:
+	}
+	printf("%d\n", safe);
+}

2/mainB.c

@@ -0,0 +1,110 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+#define LINES 1000
+
+// power! x to the y!
+int pow(int x, int y)
+{
+	int ans = 1;
+	for (int i = 0; i < y; i++) ans *= x;
+	return ans;
+}
+// parse string into array of numbers
+int parse_numbers(char *str_row, int *row, int n)
+{
+	int i = 0;
+	for (; str_row[i] != '\n'; i++);
+	for (; i >= 0; i--) {
+		int pos = 0;
+		for (; str_row[i] >= '0' && str_row[i] <= '9' && i >= 0; i--) {
+			row[n] += (str_row[i] - '0') * pow(10, pos);
+			pos++;
+		}
+		n--;
+	}
+
+	return 1;
+}
+// check if specific report is safe
+int check_report(int *row, int len)
+{
+	// read number. Compare next number (higher, lower, +-1-2)
+	// if you get to row[i + 1]line, ++
+	bool rising = 0;
+	bool first = 1;
+	for (int i = 0; i < len - 1; i++) {
+		// if difference isnt 1-3
+		if (abs(row[i + 1] - row[i]) > 3 || abs(row[i + 1] - row[i]) < 1)
+			return 0;
+		// only for first comparison of row. Set direction.
+		if (first && ((row[i + 1] - row[i]) < 0))
+			rising = 0;
+		else if (first)
+			rising = 1;
+		// for other comparisons, compare current direction to the previous.
+		if (!first && (rising != !((row[i + 1] - row[i]) < 0))) {
+			// printf("rising: %d while %d - %d is %d\n", rising, row[i + 1], row[i], row[i + 1] - row[i]);
+			return 0;
+		}
+		// get ready for the next comparisons!
+		first = 0;
+	}
+	return 1;
+}
+
+int dampener(int *row, int len)
+{
+	if (check_report(row, len))
+		return 1;
+
+	for (int i = 0; i < len; i++) {
+		int *dampened_row = malloc((len - 1) * sizeof(int));
+		// initialize shorter array, but skip element i
+		bool skipped = 0;
+		for (int j = 0; j < len - 1; j++) {
+			if (j != i && !skipped) {
+				dampened_row[j] = row[j];
+			}
+			else {
+				dampened_row[j] = row[j + 1];
+				skipped = 1;
+			}
+		}
+		if (check_report(dampened_row, len - 1)) {
+			free(dampened_row);
+			return 1;
+		}
+		free(dampened_row);
+	}
+
+	return 0;
+}
+
+int main()
+{
+	int safe = 0;
+	// read input row into array, count elements
+	FILE *input;
+	input = fopen("./input", "r");
+	char line[32];
+	for (int i = 0; i < LINES; i++) {
+		// get string (line), count numbers, put into int array (row)
+		int numbers = 1;
+		fgets(line, sizeof(line), input);
+		// count number of numbers, allocate memory
+		for (int c = 0; line[c]; c++) numbers += (line[c] == ' ');
+		int *row = (int *)calloc(numbers, sizeof(int));
+		// parse numbers into array
+		parse_numbers(line, row, numbers);
+		// for (int j = 0; j < numbers; j++) printf("%d ", row[j]);
+		// printf("\n\n");
+
+		// send elements and length to check_report, add result to sum
+		safe += dampener(row, numbers);
+		free(row);
+	}
+
+	printf("%d\n", safe);
+}

README.md

@@ -0,0 +1 @@
+plz be nice