Loading tokens…
;
+ if (error) return Failed to load prices: {error}
;
+
+ if (status === 'success') {
+ return (
+
+
+ );
+ }
+
+ return (
+
+ );
+}
diff --git a/src/problem2/src/TokenIcon.tsx b/src/problem2/src/TokenIcon.tsx
new file mode 100644
index 0000000000..dc7836d2fb
--- /dev/null
+++ b/src/problem2/src/TokenIcon.tsx
@@ -0,0 +1,23 @@
+import { useState } from 'react';
+import { tokenIconUrl } from './tokenIconUrl';
+
+export function TokenIcon({ symbol }: { symbol: string }) {
+ const [failed, setFailed] = useState(false);
+
+ if (failed) {
+ return (
+
+ );
+ }
+
+ return (
+ Swap complete
++ Swapped {amount} {fromToken?.symbol} for {receiveAmount?.toFixed(6)} {toToken?.symbol} +
+ +
+
+
+ {open && (
+
+ );
+}
diff --git a/src/problem2/src/index.css b/src/problem2/src/index.css
new file mode 100644
index 0000000000..db8e20aca7
--- /dev/null
+++ b/src/problem2/src/index.css
@@ -0,0 +1,14 @@
+:root {
+ color-scheme: light dark;
+ font-family: 'Inter', system-ui, Arial, Helvetica, sans-serif;
+}
+
+* {
+ box-sizing: border-box;
+}
+
+body {
+ margin: 0;
+ min-width: 360px;
+ min-height: 100vh;
+}
diff --git a/src/problem2/src/main.tsx b/src/problem2/src/main.tsx
new file mode 100644
index 0000000000..bef5202a32
--- /dev/null
+++ b/src/problem2/src/main.tsx
@@ -0,0 +1,10 @@
+import { StrictMode } from 'react'
+import { createRoot } from 'react-dom/client'
+import './index.css'
+import App from './App.tsx'
+
+createRoot(document.getElementById('root')!).render(
+
+ setQuery(e.target.value)}
+ />
+
+ )}
+ -
+ {filtered.length === 0 && (
+
- No tokens found + )} + {filtered.map((token) => ( +
- + + + ))} +
+ {rows}
+ {children}
+
+ );
+};
+
+export default WalletPage;
diff --git a/src/problem4/sum_to_n.ts b/src/problem4/sum_to_n.ts
new file mode 100644
index 0000000000..33377e2928
--- /dev/null
+++ b/src/problem4/sum_to_n.ts
@@ -0,0 +1,28 @@
+// Three unique implementations of sum_to_n(n) = 1 + 2 + ... + n
+
+// a) Iterative loop
+// Time: O(n) — one addition per iteration
+// Space: O(1) — single accumulator
+function sum_to_n_a(n: number): number {
+ let sum = 0;
+ for (let i = 1; i <= n; i++) sum += i;
+ return sum;
+}
+
+// b) Mathematical formula (Gauss sum)
+// Time: O(1) — constant number of arithmetic ops regardless of n
+// Space: O(1)
+// Fastest and most scalable; the only one safe for very large n.
+function sum_to_n_b(n: number): number {
+ return (n * (n + 1)) / 2;
+}
+
+// c) Recursive
+// Time: O(n) — n recursive calls
+// Space: O(n) — call stack grows with n, risks a stack overflow for large n
+function sum_to_n_c(n: number): number {
+ if (n <= 0) return 0;
+ return n + sum_to_n_c(n - 1);
+}
+
+export { sum_to_n_a, sum_to_n_b, sum_to_n_c };
diff --git a/src/problem5/.gitignore b/src/problem5/.gitignore
new file mode 100644
index 0000000000..4e99c0694a
--- /dev/null
+++ b/src/problem5/.gitignore
@@ -0,0 +1,4 @@
+node_modules
+dist
+data.json
+*.log
diff --git a/src/problem5/.keep b/src/problem5/.keep
deleted file mode 100644
index e69de29bb2..0000000000
diff --git a/src/problem5/README.md b/src/problem5/README.md
new file mode 100644
index 0000000000..4fa1b164db
--- /dev/null
+++ b/src/problem5/README.md
@@ -0,0 +1,85 @@
+# Problem 5 — A Crude Server
+
+CRUD REST API for a `Resource` entity, built with Express + TypeScript,
+persisted to a JSON file on disk via [lowdb](https://github.com/typicode/lowdb)
+(v1, synchronous file adapter — no native build step, just a real file that
+survives restarts).
+
+## Resource shape
+
+```json
+{
+ "id": "uuid",
+ "name": "string (required)",
+ "description": "string",
+ "category": "string",
+ "price": "number >= 0",
+ "createdAt": "ISO date",
+ "updatedAt": "ISO date"
+}
+```
+
+## Configuration
+
+Environment variables (optional, both have defaults):
+
+| Variable | Default | Description |
+|-----------|-------------------------|--------------------------------------|
+| `PORT` | `3000` | HTTP port the server listens on |
+| `DB_FILE` | `