add day three solution and input

2024/day3/day-three.ts

@@ -0,0 +1,87 @@
+import fs from "fs";
+
+const input = fs.readFileSync("input.txt", "utf8");
+
+//const sampleInput = `xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))`;
+const sampleInput = `xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))`;
+
+const calculateMultiplications = (input: string, part: number) => {
+  let result = 0;
+  let doMultiply = 1;
+  const inputArr = input.split("");
+
+  for (let i = 0; i < inputArr.length; i++) {
+    if (part === 2) {
+      if (input.slice(i, i + 4) === "do()") {
+        doMultiply = 1;
+      }
+      if (input.slice(i, i + 7) === "don't()") {
+        doMultiply = 2;
+      }
+    }
+
+    if (doMultiply === 1 && input.slice(i, i + 4) === "mul(") {
+      let firstNumber = "";
+      let firstNumberDigits = 0;
+      let secondNumber = "";
+
+      // Get the first number
+      if (!isNaN(parseInt(input[i + 4])) && input[i + 5] === ",") {
+        firstNumber = input[i + 4];
+        firstNumberDigits = 1;
+      } else if (
+        !isNaN(parseInt(input[i + 4])) &&
+        !isNaN(parseInt(input[i + 5])) &&
+        input[i + 6] === ","
+      ) {
+        firstNumber = `${input[i + 4]}${input[i + 5]}`;
+        firstNumberDigits = 2;
+      } else if (
+        !isNaN(parseInt(input[i + 4])) &&
+        !isNaN(parseInt(input[i + 5])) &&
+        !isNaN(parseInt(input[i + 6])) &&
+        input[i + 7] === ","
+      ) {
+        firstNumber = `${input[i + 4]}${input[i + 5]}${input[i + 6]}`;
+        firstNumberDigits = 3;
+      }
+      // Get the second number
+      if (firstNumberDigits > 0) {
+        if (
+          !isNaN(parseInt(input[i + 5 + firstNumberDigits])) &&
+          input[i + 6 + firstNumberDigits] === ")"
+        ) {
+          secondNumber = input[i + 5 + firstNumberDigits];
+        } else if (
+          !isNaN(parseInt(input[i + 5 + firstNumberDigits])) &&
+          !isNaN(parseInt(input[i + 6 + firstNumberDigits])) &&
+          input[i + 7 + firstNumberDigits] === ")"
+        ) {
+          secondNumber = `${input[i + 5 + firstNumberDigits]}${
+            input[i + 6 + firstNumberDigits]
+          }`;
+        } else if (
+          !isNaN(parseInt(input[i + 5 + firstNumberDigits])) &&
+          !isNaN(parseInt(input[i + 6 + firstNumberDigits])) &&
+          !isNaN(parseInt(input[i + 7 + firstNumberDigits])) &&
+          input[i + 8 + firstNumberDigits] === ")"
+        ) {
+          secondNumber = `${input[i + 5 + firstNumberDigits]}${
+            input[i + 6 + firstNumberDigits]
+          }${input[i + 7 + firstNumberDigits]}`;
+        }
+      }
+      // Multiply valid instruction
+      if (firstNumber && secondNumber) {
+        result += parseInt(firstNumber) * parseInt(secondNumber);
+      }
+    }
+  }
+  return result;
+};
+
+console.log(calculateMultiplications(sampleInput, 1));
+console.log(calculateMultiplications(sampleInput, 2));
+
+console.log(calculateMultiplications(input, 1));
+console.log(calculateMultiplications(input, 2));