From 4d86c701689d18bb21e23233186753080f879fd3 Mon Sep 17 00:00:00 2001
From: newt <hi@newty.dev>
Date: Wed, 9 Oct 2024 18:02:35 +0100
Subject: [PATCH] (euler): #11

---
 euler/src/11 - Largest Product in a Grid.ts | 79 +++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 euler/src/11 - Largest Product in a Grid.ts

diff --git a/euler/src/11 - Largest Product in a Grid.ts b/euler/src/11 - Largest Product in a Grid.ts
new file mode 100644
index 0000000..aafe102
--- /dev/null
+++ b/euler/src/11 - Largest Product in a Grid.ts	
@@ -0,0 +1,79 @@
+// What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20×20 grid?
+export {};
+
+const largestProductInGrid = (grid: number[][], adjacentDigits: number) => {
+    let answer = 0;
+    let product = 0;
+
+    for (let i = 0; i < grid.length; i++) {
+        const row = grid[i];
+
+        for (let j = 0; j < row.length; j++) {
+            if (j < row.length - adjacentDigits - 1) {
+                // Horizontal
+                product = grid[i][j];
+
+                for (let k = 1; k < adjacentDigits; k++) {
+                    product *= grid[i][j + k];
+                }
+            }
+            if (i < grid.length - adjacentDigits - 1) {
+                // Vertical
+                product = grid[i][j];
+
+                for (let k = 1; k < adjacentDigits; k++) {
+                    product *= grid[i + k][j];
+                }
+
+                // Diagonally to the right
+                if (j < row.length - adjacentDigits - 1) {
+                    product = grid[i][j];
+
+                    for (let k = 1; k < adjacentDigits; k++) {
+                        product *= grid[i + k][j + k];
+                    }
+                }
+
+                // Diagonally to the left
+                if (j > adjacentDigits - 1) {
+                    product = grid[i][j];
+
+                    for (let k = 1; k < adjacentDigits; k++) {
+                        product *= grid[i + k][j - k];
+                    }
+                }
+            }
+
+            answer = product > answer ? product : answer;
+        }
+    }
+    return answer;
+};
+
+console.log(
+    largestProductInGrid(
+        [
+            [8, 2, 22, 97, 38, 15, 0, 40, 0, 75, 4, 5, 7, 78, 52, 12, 50, 77, 91, 8],
+            [49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 4, 56, 62, 0],
+            [81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 3, 49, 13, 36, 65],
+            [52, 70, 95, 23, 4, 60, 11, 42, 69, 24, 68, 56, 1, 32, 56, 71, 37, 2, 36, 91],
+            [22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80],
+            [24, 47, 32, 60, 99, 3, 45, 2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50],
+            [32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70],
+            [67, 26, 20, 68, 2, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94, 21],
+            [24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72],
+            [21, 36, 23, 9, 75, 0, 76, 44, 20, 45, 35, 14, 0, 61, 33, 97, 34, 31, 33, 95],
+            [78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 3, 80, 4, 62, 16, 14, 9, 53, 56, 92],
+            [16, 39, 5, 42, 96, 35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85, 57],
+            [86, 56, 0, 48, 35, 71, 89, 7, 5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58],
+            [19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 4, 89, 55, 40],
+            [4, 52, 8, 83, 97, 35, 99, 16, 7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66],
+            [88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69],
+            [4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 8, 46, 29, 32, 40, 62, 76, 36],
+            [20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 4, 36, 16],
+            [20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 5, 54],
+            [1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48]
+        ],
+        4
+    )
+);