Session 01
Phase 1, Session 1 — Div 2 A Warmup
Target: 5 problems — implementation + math + basic logic Rating band: 800–1000
Problem 1 — Watermelon (CF 4A)
Link: https://codeforces.com/problemset/problem/4/A
Is it possible to split a watermelon weighing
wkg into two parts, each weighing an even number of kg?
Tag: Implementation, math, brute force
Problem 2 — Way Too Long Words (CF 71A)
Link: https://codeforces.com/problemset/problem/71/A
If word length > 10, replace with
first_letter + (len-2) + last_letter.
Tag: Implementation, strings
Problem 3 — Team (CF 231A)
Link: https://codeforces.com/problemset/problem/231/A
3 friends per problem. If ≥ 2 are sure (1), they'll solve it. Count problems solved.
Tag: Implementation, brute force
Problem 4 — Theatre Square (CF 1A)
Link: https://codeforces.com/problemset/problem/1/A
n×m rectangle, a×a flagstones. Minimum flagstones to cover. (Ceiling math)
Tag: Math, implementation
Key: ceil(n/a) * ceil(m/a) — careful with integer overflow
Problem 5 — Next Round (CF 158A)
Link: https://codeforces.com/problemset/problem/158/A
k-th place finisher score. Count contestants with score ≥ that and > 0.
Tag: Implementation, arrays
How to approach:
- Solve in any language (Go or Python — Go preferred for CF speed)
- Run against sample tests
- Submit on CF and check verdict
- If stuck >20 min → peep editorial, understand the trick, move on
After each problem, ask yourself:
- Could I have solved this faster?
- What was the one edge case I missed?
- Is there a simpler mathematical way?