Add solution #1036

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,107 LeetCode solutions in JavaScript
+# 1,108 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -843,6 +843,7 @@
 1033|[Moving Stones Until Consecutive](./solutions/1033-moving-stones-until-consecutive.js)|Medium|
 1034|[Coloring A Border](./solutions/1034-coloring-a-border.js)|Medium|
 1035|[Uncrossed Lines](./solutions/1035-uncrossed-lines.js)|Medium|
+1036|[Escape a Large Maze](./solutions/1036-escape-a-large-maze.js)|Hard|
 1037|[Valid Boomerang](./solutions/1037-valid-boomerang.js)|Easy|
 1038|[Binary Search Tree to Greater Sum Tree](./solutions/1038-binary-search-tree-to-greater-sum-tree.js)|Medium|
 1041|[Robot Bounded In Circle](./solutions/1041-robot-bounded-in-circle.js)|Medium|

solutions/1036-escape-a-large-maze.js

@@ -0,0 +1,66 @@
+/**
+ * 1036. Escape a Large Maze
+ * https://leetcode.com/problems/escape-a-large-maze/
+ * Difficulty: Hard
+ *
+ * There is a 1 million by 1 million grid on an XY-plane, and the coordinates of each grid
+ * square are (x, y).
+ *
+ * We start at the source = [sx, sy] square and want to reach the target = [tx, ty] square.
+ * There is also an array of blocked squares, where each blocked[i] = [xi, yi] represents
+ * a blocked square with coordinates (xi, yi).
+ *
+ * Each move, we can walk one square north, east, south, or west if the square is not in
+ * the array of blocked squares. We are also not allowed to walk outside of the grid.
+ *
+ * Return true if and only if it is possible to reach the target square from the source
+ * square through a sequence of valid moves.
+ */
+
+/**
+ * @param {number[][]} blocked
+ * @param {number[]} source
+ * @param {number[]} target
+ * @return {boolean}
+ */
+var isEscapePossible = function(blocked, source, target) {
+  const MAX = 1e6;
+  const LIMIT = 19900;
+  const blockedSet = new Set(blocked.map(([x, y]) => `${x},${y}`));
+
+  if (!helper(source, target)) {
+    return false;
+  }
+
+  return helper(target, source);
+
+  function helper(start, goal) {
+    const queue = [start];
+    const visited = new Set([`${start[0]},${start[1]}`]);
+    const directions = [[0, 1], [1, 0], [0, -1], [-1, 0]];
+
+    while (queue.length && visited.size <= LIMIT) {
+      const [x, y] = queue.shift();
+
+      for (const [dx, dy] of directions) {
+        const newX = x + dx;
+        const newY = y + dy;
+        const key = `${newX},${newY}`;
+
+        if (newX < 0 || newX >= MAX || newY < 0 || newY >= MAX
+            || blockedSet.has(key) || visited.has(key)) {
+          continue;
+        }
+
+        if (newX === goal[0] && newY === goal[1]) {
+          return true;
+        }
+
+        queue.push([newX, newY]);
+        visited.add(key);
+      }
+    }
+
+    return visited.size > LIMIT;
+  }
+};