src/Day03.java

@@ -56,4 +56,53 @@ public class Day03 extends Input {
 
         return rValue;
     }
+
+    public int part1(){
+        int rValue = 0;
+
+        for(String input : this.input.getInput()) {
+            String pattern = "mul(";
+            String num1_s = "";
+            String num2_s = "";
+            String nums = "0123456789";
+            int num = 1;
+            int pattern_cnt = 0;
+            for (int i = 0; i < input.length(); i += 1) {
+                if (pattern_cnt != pattern.length()) {
+                    if (input.charAt(i) == pattern.charAt(pattern_cnt)) {
+                        pattern_cnt += 1;
+                    } else {
+                        pattern_cnt = 0;
+                    }
+                } else {
+                    if (nums.contains(Character.toString(input.charAt(i)))) {
+                        if (num == 1) {
+                            num1_s += input.charAt(i);
+                        } else if (num == 2) {
+                            num2_s += input.charAt(i);
+                        } else {
+                            System.err.println("Something went wrong");
+                        }
+                    } else if (input.charAt(i) == ',' && num == 1) {
+                        num += 1;
+                    } else if (input.charAt(i) == ')' && num == 2) {
+                        int num1 = Integer.parseInt(num1_s);
+                        int num2 = Integer.parseInt(num2_s);
+                        rValue += (num1 * num2);
+                        num = 1;
+                        pattern_cnt = 0;
+                        num1_s = "";
+                        num2_s = "";
+                    } else {
+                        num = 1;
+                        pattern_cnt = 0;
+                        num1_s = "";
+                        num2_s = "";
+                    }
+                }
+            }
+        }
+
+        return rValue;
+    }
 }

src/Main.java

@@ -24,6 +24,14 @@ public class Main {
         int d1_p2_answer = day01.Part2();
         long day01_p2 = System.currentTimeMillis() - start;
 
+        start = System.currentTimeMillis();
+        Day03 day03 = new Day03();
+        long day03_init = System.currentTimeMillis() - start;
+
+        start = System.currentTimeMillis();
+        int day03_p1_sample = day03.part1_sample();
+        long day03_p1_sample_t = System.currentTimeMillis() - start;
+
         System.out.printf("Day 1 init took %dms", day01_init);
         System.out.printf("Part 1 sample is: %d (%dms)\n", sample_d1_p1_answer, day01_p1_sample);
         System.out.printf("Part 1 answer is: %d (%dms)\n", d1_p1_answer, day01_p1);