Solve 10

src/10/index.ts

@@ -0,0 +1,87 @@
+import fs from "fs"
+const content = fs.readFileSync('input.txt', 'utf-8');
+
+interface Point {
+    x: number
+    y: number
+}
+
+const heightMap = content.split("\r\n").map(row => row.split("").map(char => Number(char)))
+const height = heightMap.length
+const width = heightMap[0].length
+const peakSet = new Set();
+function walk(point: Point) {
+    const pos = heightMap[point.y][point.x]
+    if (pos === 9) {
+        peakSet.add("" + point.x + point.y)
+    } else {
+        const walkable:Point[] = []
+        if (point.y-1 >=0 && (heightMap[point.y-1][point.x]-pos ===1)) {
+            walkable.push({x:point.x, y: point.y-1})
+        }
+        if (point.y+1 < height && (heightMap[point.y+1][point.x]-pos ===1)) {
+            walkable.push({x:point.x, y: point.y+1})
+        }
+        if (point.x-1 >=0 && (heightMap[point.y][point.x-1]-pos ===1)) {
+            walkable.push({x:point.x-1, y: point.y})
+        }
+        if (point.x+1 < width && (heightMap[point.y][point.x+1]-pos === 1)) {
+            walkable.push({x:point.x+1, y: point.y})
+        }
+        if (walkable.length > 0){
+            for (let i = 0; i < walkable.length; i++) {
+                walk(walkable[i])
+            }
+        }
+    }
+}
+function walk2(point: Point) {
+    const pos = heightMap[point.y][point.x]
+    if (pos === 9) {
+        peakSet.add({x: point.x, y:point.y})
+    } else {
+        const walkable:Point[] = []
+        if (point.y-1 >=0 && (heightMap[point.y-1][point.x]-pos ===1)) {
+            walkable.push({x:point.x, y: point.y-1})
+        }
+        if (point.y+1 < height && (heightMap[point.y+1][point.x]-pos ===1)) {
+            walkable.push({x:point.x, y: point.y+1})
+        }
+        if (point.x-1 >=0 && (heightMap[point.y][point.x-1]-pos ===1)) {
+            walkable.push({x:point.x-1, y: point.y})
+        }
+        if (point.x+1 < width && (heightMap[point.y][point.x+1]-pos === 1)) {
+            walkable.push({x:point.x+1, y: point.y})
+        }
+        if (walkable.length > 0){
+            for (let i = 0; i < walkable.length; i++) {
+                walk2(walkable[i])
+            }
+        }
+    }
+}
+
+let pathcount = 0;
+for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+        const pos = heightMap[y][x]
+        if (pos === 0) {
+            peakSet.clear();
+            walk({x:x,y:y})
+            pathcount += peakSet.size;
+        }
+    }
+}
+console.log(pathcount)
+pathcount = 0;
+for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+        const pos = heightMap[y][x]
+        if (pos === 0) {
+            peakSet.clear();
+            walk2({x:x,y:y})
+            pathcount += peakSet.size;
+        }
+    }
+}
+console.log(pathcount)