Day 3 part 2

src/Day03_02.sol

@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.13;
+
+import {LibString} from "solady/src/utils/LibString.sol";
+import {LibBytesUint} from "./LibBytesUint.sol";
+
+struct Point {
+    uint256 x;
+    uint256 y;
+}
+
+struct Rectangle {
+    Point start;
+    Point end;
+    uint256 value;
+    bool valueSet;
+}
+
+function intersects(Rectangle memory a, Rectangle memory b) pure returns (bool) {
+    if (a.start.x > b.end.x || b.start.x > a.end.x) {
+        return false;
+    }
+
+    if (a.end.y < b.start.y || b.end.y < a.start.y) {
+        return false;
+    }
+
+    return true;
+}
+
+contract Day03_02 {
+    Rectangle[] numberRectangles;
+    Rectangle[] symbolImpactAreas;
+
+    uint256 lineIndex;
+
+    bytes1 constant CHAR_ASTERISK = 0x2a;
+    bytes1 constant CHAR_DOT = 0x2e;
+    uint256 constant ASTERISK_VALUE_INDICATOR = 7777777777777777;
+
+    function parseLine(string calldata line) public virtual {
+        bytes memory lineBytes = bytes(line);
+        uint256 numberVectorLength;
+        uint256 totalNumber;
+
+        for (uint256 i; i < lineBytes.length; i++) {
+            bool isDigit = LibBytesUint.isDigit(lineBytes[i]);
+            if (isDigit) {
+                uint256 digit = uint256(uint8(bytes1(lineBytes[i]))) - 48;
+                totalNumber = totalNumber * 10 + digit;
+                numberVectorLength++;
+            }
+
+            if (totalNumber != 0 && (!isDigit || i == lineBytes.length - 1)) {
+                numberRectangles.push(
+                    Rectangle({
+                        start: Point(i - numberVectorLength, lineIndex),
+                        end: Point(i - 1, lineIndex),
+                        value: totalNumber,
+                        valueSet: true
+                    })
+                );
+                delete numberVectorLength;
+                delete totalNumber;
+            }
+
+            if (lineBytes[i] != CHAR_DOT && !isDigit) {
+                symbolImpactAreas.push(
+                    Rectangle({
+                        start: Point(i == 0 ? 0 : i - 1, lineIndex == 0 ? 0 : lineIndex - 1),
+                        end: Point(i + 1, lineIndex + 1),
+                        value: lineBytes[i] == CHAR_ASTERISK ? ASTERISK_VALUE_INDICATOR : 0,
+                        valueSet: false
+                    })
+                );
+            }
+        }
+
+        lineIndex++;
+    }
+
+    function computeResult() public view returns (uint256) {
+        uint256 result;
+
+        for (uint256 j; j < symbolImpactAreas.length; j++) {
+            if (symbolImpactAreas[j].value != ASTERISK_VALUE_INDICATOR) {
+                continue;
+            }
+
+            uint256 intersections_value = 1;
+            uint256 intersections_count = 0;
+            for (uint256 i; i < numberRectangles.length; i++) {
+                if (intersects(numberRectangles[i], symbolImpactAreas[j])) {
+                    intersections_value *= numberRectangles[i].value;
+                    intersections_count++;
+
+                    if (intersections_count == 2) {
+                        result += intersections_value;
+                        break;
+                    }
+                }
+            }
+        }
+
+        return result;
+    }
+}

test/Day03.sol

@@ -3,12 +3,15 @@ pragma solidity ^0.8.13;
 
 import {Test, console2} from "forge-std/Test.sol";
 import {Day03_01} from "../src/Day03_01.sol";
+import {Day03_02} from "../src/Day03_02.sol";
 
 contract Day03Test is Test {
     Day03_01 public day03_01;
+    Day03_02 public day03_02;
 
     function setUp() public {
         day03_01 = new Day03_01();
+        day03_02 = new Day03_02();
     }
 
     function test_day03_01_demo() public {
@@ -40,4 +43,34 @@ contract Day03Test is Test {
         console2.log("Day 3_1: ", result);
         assertEq(result, 522726);
     }
+
+    function test_day03_02_demo() public {
+        while (true) {
+            string memory line = vm.readLine("./inputs/03_demo.txt");
+            if (bytes(line).length == 0) {
+                break;
+            }
+
+            day03_02.parseLine(line);
+        }
+
+        uint256 result = day03_02.computeResult();
+        console2.log("Day 3_2 (demo): ", result);
+        assertEq(result, 467835);
+    }
+
+    function test_day03_02() public {
+        while (true) {
+            string memory line = vm.readLine("./inputs/03.txt");
+            if (bytes(line).length == 0) {
+                break;
+            }
+
+            day03_02.parseLine(line);
+        }
+
+        uint256 result = day03_02.computeResult();
+        console2.log("Day 3_2: ", result);
+        assertEq(result, 81721933);
+    }
 }