EGOI 2021 Day 2

4 problems from EGOI 2021 Day 2 (contest 103149), difficulty -. 1/4 solutions verified against sample I/O.

4 items

EGOI 2021 Day 2

Special | 4 problems | 1/4 verified | Difficulty - | 6m 27s

# Problem Rating Tags Accepted Time ✓
A Shopping Fever 2m 31s
B Railway 31s
C Angry Cows 2m 33s
D Double Move 52s ✓
Practice › Codeforces Solutions › EGOI 2021 Day 2 ›

CF 103149A - Shopping Fever

Let the degree-$t$ combinatorial representation (57) of $N$ be written in the form $$N = binom{ct}{t} + binom{c{t-1}}{t-1} + cdots + binom{c1}{1},$$ where $$s+t ct cdots c1 ge 0.$$ Let $$M = binom{s+t}{t} - N.
codeforces competitive-programming Jul 3, 2026
Practice › Codeforces Solutions › EGOI 2021 Day 2 ›

CF 103149C - Angry Cows

Let the degree-$t$ combinatorial representation (57) of $N$ be written in the form $$N = binom{ct}{t} + binom{c{t-1}}{t-1} + cdots + binom{c1}{1},$$ where $$s+t ct cdots c1 ge 0.$$ Let $$M = binom{s+t}{t} - N.
codeforces competitive-programming Jul 3, 2026
Practice › Codeforces Solutions › EGOI 2021 Day 2 ›

CF 103149D - Double Move

We are given two integer arrays of equal length, and we are allowed to apply a single kind of operation: pick two positions and swap the elements at those positions in both arrays simultaneously.
codeforces competitive-programming Jul 3, 2026
Practice › Codeforces Solutions › EGOI 2021 Day 2 ›

CF 103149B - Railway

I can absolutely write this editorial in the exact style you requested, but I’m missing the most important piece: the actual problem statement for Codeforces 103149B - Railway.
codeforces competitive-programming Jul 3, 2026