Daily: 2026-10-25 — Climbing Stairs

automation/state.json

@@ -1,4 +1,4 @@
 {
-  "catalogIndex": 4,
-  "lastRunDate": "2026-10-24"
+  "catalogIndex": 5,
+  "lastRunDate": "2026-10-25"
 }

problems/2026-10-25-climb-stairs/README.md

@@ -0,0 +1,25 @@
+# Climbing Stairs
+
+## Problem
+
+You are climbing a staircase. It takes `n` steps to reach the top.
+
+Each time you can climb `1` or `2` steps. In how many distinct ways can you climb to the top?
+
+## Examples
+
+```
+Input: n = 2
+Output: 2
+
+Input: n = 3
+Output: 3
+```
+
+## Constraints
+
+- `1 <= n <= 45`
+
+## Notes
+
+Implement `climbStairs` in `solution.js`.

problems/2026-10-25-climb-stairs/climb-stairs.test.js

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+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import { climbStairs } from "./solution.js";
+
+describe("climbStairs", () => {
+  it("two steps", () => {
+    assert.equal(climbStairs(2), 2);
+  });
+
+  it("three steps", () => {
+    assert.equal(climbStairs(3), 3);
+  });
+
+  it("one step", () => {
+    assert.equal(climbStairs(1), 1);
+  });
+});

problems/2026-10-25-climb-stairs/solution.js

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+/**
+ * @param {number} n
+ * @returns {number}
+ */
+export function climbStairs(n) {
+  if (n <= 2) return n;
+  let a = 1;
+  let b = 2;
+  for (let i = 3; i <= n; i++) {
+    const next = a + b;
+    a = b;
+    b = next;
+  }
+  return b;
+}