Educational Codeforces Round 172 (Rated for Div. 2)

6 problems from Educational Codeforces Round 172 (Rated for Div. 2) (contest 2042), difficulty 800-2900. 0/6 solutions verified against sample I/O.

6 items

Educational Codeforces Round 172 (Rated for Div. 2)

Div. 2 | 6 problems | 0/6 verified | Difficulty 800-2900 | 13m 59s

# Problem Rating Tags Accepted Time ✓
A Greedy Monocarp 800 greedy, sortings 20,853 1m 36s
B Game with Colored Marbles 900 games, greedy 19,484 2m 26s
C Competitive Fishing 1800 greedy 8,643 2m 9s
D Recommendations 1900 data-structures, implementation, sortings 5,233 3m 15s
E Vertex Pairs 2900 binary-search, brute-force, data-structures 524 2m 4s
F Two Subarrays 2600 data-structures, dp, implementation 907 2m 29s
Practice › Codeforces Solutions › Educational Codeforces Round 172 (Rated for Div. 2) ›

CF 2042F - Two Subarrays

We have two arrays, a and b. For any subarray [l, r], its value is not just the sum of the elements of a inside it. We also add bl and br, the values attached to the two endpoints.
codeforces competitive-programming data-structures dp implementation matrices Jun 8, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 172 (Rated for Div. 2) ›

CF 2042D - Recommendations

Each user in the system is described by a closed interval on the number line. If we think of track IDs as positions on a huge axis from 1 to 10^9, then user i likes exactly the integer points in the segment $[li, ri]$.
codeforces competitive-programming data-structures implementation sortings two-pointers Jun 8, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 172 (Rated for Div. 2) ›

CF 2042E - Vertex Pairs

The failure you show is not enough to diagnose the algorithm itself. Let's trace what happened: The input contains 5 test cases: The program produced only: instead of: This means the code successfully processed the first test case and then terminated before handling the…
codeforces competitive-programming binary-search brute-force data-structures dfs-and-similar divide-and-conquer greedy implementation trees Jun 8, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 172 (Rated for Div. 2) ›

CF 2042B - Game with Colored Marbles

We are asked to compute Alice's final score in a sequential marble-taking game. There is a collection of n marbles, each with a specific color. Alice and Bob alternate turns, starting with Alice. Each turn consists of removing one marble.
codeforces competitive-programming games greedy Jun 8, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 172 (Rated for Div. 2) ›

CF 2042C - Competitive Fishing

The failure you show is not enough to diagnose the algorithm itself. Let's trace what happened: The input contains 5 test cases: The program produced only: instead of: This means the code successfully processed the first test case and then terminated before handling the…
codeforces competitive-programming greedy Jun 8, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 172 (Rated for Div. 2) ›

CF 2042A - Greedy Monocarp

We are given several independent test cases. In each one there is a collection of chests, each starting with some number of coins. We are allowed to increase the number of coins in any chests, with no limit on how many we add, but we are trying to minimize the total coins we add.
codeforces competitive-programming greedy sortings Jun 8, 2026