[BE] Code Challenge - Nguyen Thanh Rin

src/problem4/sum-to-n.ts

@@ -0,0 +1,27 @@
+//Implementation A: Iterative loop
+export const sum_to_n_a = (n: number): number => {
+  if (n <= 0) return 0;
+
+  let sum = 0;
+  for (let i = 1; i <= n; i++) {
+    sum += i;
+  }
+  return sum;
+};
+
+// Implementation B: Mathematical formula
+export const sum_to_n_b = (n: number): number => {
+  if (n <= 0) return 0;
+
+  return (n * (n + 1)) / 2;
+};
+
+// Implementation C: Functional style (Array + reduce)
+export const sum_to_n_c = (n: number): number => {
+  if (n <= 0) return 0;
+
+  return Array.from({ length: n }, (_, i) => i + 1).reduce(
+    (acc, cur) => acc + cur,
+    0
+  );
+};

src/problem5/.gitignore

@@ -0,0 +1,7 @@
+node_modules/
+dist/
+data.db
+*.log
+.DS_Store
+.env
+