C2 · CrunchTime — The Code

Technical interview prep,
done right.

U
M
P
I
R
E

A free, open-source technical interview preparation course built around the UMPIRE Method — recognize patterns, explain your thinking, and walk out with the offer.

~520 hrs 15-week intensive · or · 1-year mastery GPL-3.0 14 patterns · 60+ problems · 4 mocks

Start the 15-week intensive Start the 1-year mastery Read the Course →

The method

Six steps. Same order. Out loud. Every problem.

Most candidates fail interviews not because they couldn't solve the problem — they fail because they couldn't explain themselves. UMPIRE makes the reasoning visible.

The six steps

U — Understand. Restate the problem, surface assumptions, agree on examples.

M — Match. Recognize the pattern (sliding window, BFS, DP, …).

P — Plan. Write the steps in English before any code.

I — Implement. Translate the plan to clean code, one line per sentence.

R — Review. Trace the code with a small input, find bugs first.

E — Evaluate. Analyze time and space, discuss tradeoffs, propose improvements.

By Week 4 it's automatic. By Week 10 you can do it under pressure. By Week 15 it's the reason you get the offer.

// U — UNDERSTAND # "Sorted array, return indices summing to target."
# "Exactly one solution, 1-indexed, i < j."
# Example: [2,7,11,15], t=9 → [1,2] // M — MATCH # Sorted + pair + target → two-pointer converging. // P — PLAN # l=0, r=n-1. Loop. Sum. Match→return. Less→l++. More→r--. // I — IMPLEMENT def two_sum_sorted(nums, target):
  l, r = 0, len(nums) - 1
  while l < r:
    s = nums[l] + nums[r]
    if s == target: return [l+1, r+1]
    if s < target: l += 1
    else: r -= 1
  return [-1, -1] // R — REVIEW # Trace [2,7,11,15] t=9: l=0,r=3,s=17 → r=2 → s=13 → r=1 → s=9 → [1,2] ✓ // E — EVALUATE # Time O(n). Space O(1). Hash-map alt is O(n)/O(n) — worse for sorted input.

The 14 patterns

The complete pattern library.

Every algorithmic interview problem you've heard of falls into one of these 14 patterns. Learn the patterns, not the problems.

Phase 1

Arrays + Two Pointers

Phase 1

Hash Maps

Phase 1

Sliding Window

Phase 1

Fast / Slow Pointers

Phase 2

Binary Search

Phase 2

BFS

Phase 2

DFS

Phase 2

Backtracking

Phase 2

Top-K · Heap

Phase 3

Intervals + Greedy

Phase 3

DP — 1D

Phase 3

DP — 2D

Phase 3

Bit Manipulation · Tries

Phase 4

System Design

Two pathways · same content

Pick your pace.

The 15-week intensive packs interview prep into a single hiring cycle. The 1-year mastery spreads the same material across a calendar year, the way working engineers actually sustain a practice. Same UMPIRE, same patterns, same capstone.

Intensive · 15 weeks

Cadence
~36 hours / week, full-time
Total
~540 hours
For
Bootcamp grads · career switchers · learners between jobs · anyone with a hiring cycle starting in 4 months
Mocks
4 recorded mocks at Weeks 4 / 9 / 14 / 15
Outcome
Interview-ready at FAANG and strong startups

Mastery · 1 year

Cadence
~10 hours / week, sustainable
Total
~520 hours
For
Working engineers preparing for next year's hiring season · learners balancing classes · anyone who wants depth over speed
Mocks
4 recorded mocks at quarter boundaries
Outcome
Interview-ready plus genuine algorithmic intuition you keep for years

15-week intensive · weekly map

Week by week.

W1 UMPIRE + two pointers
W2 Complexity + hash maps
W3 Sliding window
W4 Fast/slow + Mock #1
W5 Binary search
W6 BFS
W7 DFS
W8 Backtracking
W9 Top-K + Mock #2
W10 Intervals + greedy
W11 DP — 1D
W12 DP — 2D + System Design
W13 Behavioral · STAR
W14 Bit manip + tries + Mock #3
W15 Capstone + Mock #4

Capstone deliverables

What you ship.

By the end of C2 you'll publish a public GitHub repo — crunchtime-interview-prep-<yourhandle> — that becomes the artifact you point recruiters and hiring managers at.

Milestone badges

Open-source, verifiable, never sold.

C2 is not accredited. We don't pretend to be. We issue open-source verifiable milestone badges that pin to your GitHub profile and link to a portfolio entry anyone can audit. We do not charge fees. The portfolio is the credential.

UMPIREApprentice
Weeks 1–4
PatternPractitioner
Weeks 5–9
SystemThinker
Week 12
MockVeteran
4 mocks recorded
CrunchTime Graduate
Capstone shipped