Restore aoc backup.

2015/day04/answer01.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <openssl/md5.h>
+
+int main() {
+	size_t PUZZLE_SIZE = 8;		//puzzle input is 8 characters with no ending newline character
+
+	//load input string
+	FILE *file = fopen("input", "r");
+	if (file == NULL) {
+		perror("main: error opening file.");
+		return -1;
+	}
+	char input[256];
+	while (fgets(input, sizeof(input), file));
+	if (strlen(input) != PUZZLE_SIZE) {		
+		perror("main: error reading file.");
+		return -1;
+	}
+	printf("puzzle input: %s\n", input);
+	
+	//initialize MD5 context
+	//note: ignore gcc's warnings that MD5 is depreciated
+	MD5_CTX md5_context;
+	uint8_t md5_hash[MD5_DIGEST_LENGTH];
+	char md5_string[MD5_DIGEST_LENGTH * 2 + 1];	//32 hexadecimal digits
+												//each byte needs two characters in hex, plus one for '\0'
+	char *md5_string_ptr = md5_string;
+	
+	int32_t chars_written;
+	int32_t available_space;
+	int32_t count = -1;		//initialize count at -1 so that the first count++ sets it to 0
+ 	
+	while (strncmp(md5_string, "00000", 5) != 0) {
+		count++;
+		chars_written = snprintf(input + PUZZLE_SIZE, sizeof(input) - strlen(input), "%i", count);
+        available_space = sizeof(input) - strlen(input);
+		if (chars_written >= available_space) {
+			perror("main: buffer overflow.");
+			return -1;
+		}
+   	
+		//initialize MD5 context
+		MD5_Init(&md5_context);
+        
+		//update context with input (+ count) data
+		MD5_Update(&md5_context, input, strlen(input));
+
+		//finalize MD5 hash
+		MD5_Final(md5_hash, &md5_context);
+
+	    for (int i = 0; i < MD5_DIGEST_LENGTH; i++) {
+			md5_string_ptr += sprintf(md5_string_ptr, "%02x", md5_hash[i]);
+		}
+		md5_string_ptr = md5_string;	//reset pointer
+	}
+	
+	printf("count %i: %s\n", count, md5_string);
+	return 0;
+}
+

2015/day04/answer02.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <openssl/md5.h>
+
+int main() {
+	size_t PUZZLE_SIZE = 8;		//puzzle input is 8 characters with no ending newline character
+
+	//load input string
+	FILE *file = fopen("input", "r");
+	if (file == NULL) {
+		perror("main: error opening file.");
+		return -1;
+	}
+	char input[256];
+	while (fgets(input, sizeof(input), file));
+	if (strlen(input) != PUZZLE_SIZE) {		
+		perror("main: error reading file.");
+		return -1;
+	}
+	printf("puzzle input: %s\n", input);
+	
+	//initialize MD5 context
+	//note: ignore gcc's warnings that MD5 is depreciated
+	MD5_CTX md5_context;
+	uint8_t md5_hash[MD5_DIGEST_LENGTH];
+	char md5_string[MD5_DIGEST_LENGTH * 2 + 1];	//32 hexadecimal digits
+												//each byte needs two characters in hex, plus one for '\0'
+	char *md5_string_ptr = md5_string;
+	
+	int32_t chars_written;
+	int32_t available_space;
+	int32_t count = -1;		//initialize count at -1 so that the first count++ sets it to 0
+ 	
+	while (strncmp(md5_string, "000000", 6) != 0) {
+		count++;
+		chars_written = snprintf(input + PUZZLE_SIZE, sizeof(input) - strlen(input), "%i", count);
+        available_space = sizeof(input) - strlen(input);
+		if (chars_written >= available_space) {
+			perror("main: buffer overflow.");
+			return -1;
+		}
+   	
+		//initialize MD5 context
+		MD5_Init(&md5_context);
+        
+		//update context with input (+ count) data
+		MD5_Update(&md5_context, input, strlen(input));
+
+		//finalize MD5 hash
+		MD5_Final(md5_hash, &md5_context);
+
+	    for (int i = 0; i < MD5_DIGEST_LENGTH; i++) {
+			md5_string_ptr += sprintf(md5_string_ptr, "%02x", md5_hash[i]);
+		}
+		md5_string_ptr = md5_string;	//reset pointer
+	}
+	
+	printf("count %i: %s\n", count, md5_string);
+	return 0;
+}
+

2015/day04/input

@@ -0,0 +1 @@
+ckczppom

2015/day04/makefile

@@ -0,0 +1,10 @@
+CC = gcc
+CFLAGS = -std=c99 -Wall -g
+LDFLAGS = -lcrypto
+
+1: answer01.c
+	$(CC) $(CFLAGS) $(LDFLAGS) answer01.c -o answer01
+
+2: answer02.c
+	$(CC) $(CFLAGS) $(LDFLAGS) answer02.c -o answer02
+