unique-paths solution

Author: krokerdile

unique-paths/krokerdile.js

@@ -0,0 +1,21 @@
+/**
+ * @param {number} m
+ * @param {number} n
+ * @return {number}
+ */
+var uniquePaths = function(m, n) {
+    const memo = {};
+
+    function dfs(x, y) {
+        if (x >= m || y >= n) return 0;
+        if (x === m - 1 && y === n - 1) return 1;
+
+        const key = `${x},${y}`;
+        if (key in memo) return memo[key];
+
+        memo[key] = dfs(x + 1, y) + dfs(x, y + 1);
+        return memo[key];
+    }
+
+    return dfs(0, 0);
+};