Educational Codeforces Round 188 (Rated for Div. 2)

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ContestId
Name
Phase
Frozen
Duration (Seconds)
Relative Time
Start Time
2204 Educational Codeforces Round 188 (Rated for Div. 2) FINISHED False 8100 2733923 March 16, 2026, 2:35 p.m.

Problems

Solved
Index
Name
Type
Tags
Community Tag
Rating
( 8488 ) D Alternating Path PROGRAMMING dfs and similar graphs

You are given an undirected graph with (n) vertices and (m) edges. The vertices are numbered from (1) to (n). The graph contains no self-loops or multiple edges. Your task is to make a graph directed by choosing a direction for each edge. After directing the edges, call a sequence of vertices (v_1, v_2, \dots, v_k), where (k) can be arbitrarily large and any vertex can be repeated any number of times, an alternating path if: the edge ((v_1, v_2)) is directed from (v_1) to (v_2); the edge ((v_2, v_3)) is directed from (v_3) to (v_2); the edge ((v_3, v_4)) is directed from (v_3) to (v_4); the edge ((v_4, v_5)) is directed from (v_5) to (v_4); and so on. Call a vertex (v) beautiful if all paths (not necessarily simple) in the original graph that start at vertex (v) are alternating in the resulting directed graph. What is the maximum number of vertices that can be made beautiful after directing the edges? Each test contains multiple test cases. The first line contains the number of test cases (t) ((1 \le t \le 10^4)). The description of the test cases follows. The first line contains two integers (n) and (m) ((1 \le n \le 2 \cdot 10^5); (0 \le m \le 2 \cdot 10^5)) — the number of vertices and edges in the graph, respectively. Each of the following (m) lines contains two integers (v) and (u) ((1 \le v, u \le n)) — the description of the edges of the graph. Additional constraints on the input: The given graph contains no self-loops or multiple edges; The sum of (n) over all test cases does not exceed (2 \cdot 10^5); The sum of (m) over all test cases does not exceed (2 \cdot 10^5). For each test case, print a single integer — the maximum number of vertices that can be made beautiful after directing the edges.

Tutorials

Educational Codeforces Round 188 Editorial

Submissions

Submission Id
Author(s)
Index
Submitted
Verdict
Language
Test Set
Tests Passed
Time taken (ms)
Memory Consumed (bytes)
Tags
Rating
367004213 bharatrajhentaboina D March 16, 2026, 4:22 p.m. OK C# 10 TESTS 23 375 22630400
367014951 wanna_be_cs_gaoshou D March 16, 2026, 4:58 p.m. OK C# 13 TESTS 23 531 59801600
367005130 ljw D March 16, 2026, 4:25 p.m. OK C++17 (GCC 7-32) TESTS 23 125 12083200
367043768 zyb_txdy D March 17, 2026, 1:10 a.m. OK C++17 (GCC 7-32) TESTS 23 125 13824000
367008266 chansolpark7 D March 16, 2026, 4:34 p.m. OK C++17 (GCC 7-32) TESTS 23 140 3481600
367010538 EasonGu D March 16, 2026, 4:41 p.m. OK C++17 (GCC 7-32) TESTS 23 156 10547200
367049430 fanmang D March 17, 2026, 3:39 a.m. OK C++17 (GCC 7-32) TESTS 23 156 11673600
367027643 practicepracticepractice D March 16, 2026, 7:40 p.m. OK C++17 (GCC 7-32) TESTS 23 156 13004800
367021316 block-plant D March 16, 2026, 6 p.m. OK C++17 (GCC 7-32) TESTS 23 171 3481600
367012760 yashwanthaax D March 16, 2026, 4:48 p.m. OK C++17 (GCC 7-32) TESTS 23 171 3481600
367036095 AliGorithmz D March 16, 2026, 9:45 p.m. OK C++17 (GCC 7-32) TESTS 23 171 6553600
367000116 the_domini D March 16, 2026, 4:11 p.m. OK C++17 (GCC 7-32) TESTS 23 171 6553600
367006313 wsr999 D March 16, 2026, 4:28 p.m. OK C++20 (GCC 13-64) TESTS 23 109 16998400
367038626 csj654321 D March 16, 2026, 10:36 p.m. OK C++20 (GCC 13-64) TESTS 23 109 29798400
367046080 Donaldqian0712 D March 17, 2026, 2:31 a.m. OK C++20 (GCC 13-64) TESTS 23 125 21401600
367038793 csj654321 D March 16, 2026, 10:40 p.m. OK C++20 (GCC 13-64) TESTS 23 125 32870400
367044524 Piggy07 D March 17, 2026, 1:35 a.m. OK C++20 (GCC 13-64) TESTS 23 140 6451200
367043796 FredyNC23 D March 17, 2026, 1:11 a.m. OK C++20 (GCC 13-64) TESTS 23 140 6553600
367035038 andycoke D March 16, 2026, 9:27 p.m. OK C++20 (GCC 13-64) TESTS 23 140 24576000
367043293 HungHot D March 17, 2026, 12:56 a.m. OK C++20 (GCC 13-64) TESTS 23 140 24678400
367051683 rzgbl D March 17, 2026, 4:09 a.m. OK C++20 (GCC 13-64) TESTS 23 156 6553600
367008800 ewifhu73 D March 16, 2026, 4:35 p.m. OK C++20 (GCC 13-64) TESTS 23 156 6553600
367053315 senapathidinesh.in D March 17, 2026, 4:30 a.m. OK C++23 (GCC 14-64, msys2) TESTS 23 109 3276800
367043200 Cjx D March 17, 2026, 12:54 a.m. OK C++23 (GCC 14-64, msys2) TESTS 23 109 16998400
367058649 LiuYiPing D March 17, 2026, 5:34 a.m. OK C++23 (GCC 14-64, msys2) TESTS 23 109 34611200
367044270 yanWy D March 17, 2026, 1:27 a.m. OK C++23 (GCC 14-64, msys2) TESTS 23 109 44441600
367002636 Quest1_2_3 D March 16, 2026, 4:18 p.m. OK C++23 (GCC 14-64, msys2) TESTS 23 125 4198400
367012710 sharingantaibaja D March 16, 2026, 4:48 p.m. OK C++23 (GCC 14-64, msys2) TESTS 23 125 7475200
367000940 cuidongxu D March 16, 2026, 4:13 p.m. OK C++23 (GCC 14-64, msys2) TESTS 23 125 16998400
367009893 101Noir D March 16, 2026, 4:39 p.m. OK C++23 (GCC 14-64, msys2) TESTS 23 140 102400
367005505 YS_BF D March 16, 2026, 4:26 p.m. OK C++23 (GCC 14-64, msys2) TESTS 23 140 5632000
367054546 CXPapy D March 17, 2026, 4:46 a.m. OK C++23 (GCC 14-64, msys2) TESTS 23 140 6451200
367011897 1435730 D March 16, 2026, 4:45 p.m. OK GNU C11 TESTS 23 125 11468800
367012486 ikiku D March 16, 2026, 4:47 p.m. OK Java 21 TESTS 23 375 37273600
367002903 prachiiiiii D March 16, 2026, 4:19 p.m. OK Java 21 TESTS 23 468 74240000
367003942 vrajrajput2005 D March 16, 2026, 4:21 p.m. OK Java 21 TESTS 23 515 39731200
367002178 GoodBoy15 D March 16, 2026, 4:16 p.m. OK Java 21 TESTS 23 546 41267200
367007565 mastacoda D March 16, 2026, 4:32 p.m. OK Java 21 TESTS 23 562 70451200
367019061 testtest111ksjfrdvn D March 16, 2026, 5:33 p.m. OK Java 21 TESTS 23 593 63488000
367021053 shyamPrajapat D March 16, 2026, 5:56 p.m. OK Java 21 TESTS 23 609 61644800
367005726 Thanmai_19 D March 16, 2026, 4:26 p.m. OK Java 21 TESTS 23 625 35840000
367032281 hg_2005 D March 16, 2026, 8:35 p.m. OK Java 21 TESTS 23 625 37068800
367007568 ayush15122005 D March 16, 2026, 4:32 p.m. OK Java 21 TESTS 23 640 36761600
367033952 harsh_1806 D March 16, 2026, 9:04 p.m. OK Java 8 TESTS 23 390 38502400
367004674 puranium235 D March 16, 2026, 4:23 p.m. OK Java 8 TESTS 23 515 36864000
367002931 sahupyl D March 16, 2026, 4:19 p.m. OK Java 8 TESTS 23 562 29696000
367024334 TheJavaGuy D March 16, 2026, 6:43 p.m. OK Java 8 TESTS 23 562 40857600
367006851 ousben63 D March 16, 2026, 4:30 p.m. OK Java 8 TESTS 23 656 35942400
367003467 niharikas18 D March 16, 2026, 4:20 p.m. OK Java 8 TESTS 23 1203 31334400
367031335 NeelmaniPandey09 D March 16, 2026, 8:24 p.m. OK Java 8 TESTS 23 1218 27955200
367006889 am_I_Newbie D March 16, 2026, 4:30 p.m. OK Java 8 TESTS 23 1250 27852800
367004773 jash.rashne D March 16, 2026, 4:24 p.m. OK Java 8 TESTS 23 1281 31334400
367002719 manhbnvn3102 D March 16, 2026, 4:18 p.m. OK Java 8 TESTS 23 1296 31334400
367003703 yg.margo D March 16, 2026, 4:21 p.m. OK Kotlin 2.2 TESTS 23 171 23859200
367026126 roman.yakhimovich D March 16, 2026, 7:18 p.m. OK Kotlin 2.2 TESTS 23 171 23961600
367006959 nullbrain_ D March 16, 2026, 4:30 p.m. OK Kotlin 2.2 TESTS 23 171 23961600
367002184 jagbarrameda D March 16, 2026, 4:17 p.m. OK Kotlin 2.2 TESTS 23 625 61235200
367017140 thecodekiller D March 16, 2026, 5:16 p.m. OK PyPy 2 TESTS 23 531 15769600
367001692 Srimathi_k D March 16, 2026, 4:15 p.m. OK PyPy 3 TESTS 23 734 19968000
366999829 pyl_youngboy D March 16, 2026, 4:10 p.m. OK PyPy 3 TESTS 23 1140 36147200
367045120 bpdolson D March 17, 2026, 1:59 a.m. OK PyPy 3 TESTS 23 1171 24678400
367019185 lhtmssdlw D March 16, 2026, 5:34 p.m. OK PyPy 3-64 TESTS 23 312 432537600
367009118 d3elmz D March 16, 2026, 4:36 p.m. OK PyPy 3-64 TESTS 23 328 57856000
367051808 qyzm123 D March 17, 2026, 4:11 a.m. OK PyPy 3-64 TESTS 23 343 29491200
367042524 fatalerror D March 17, 2026, 12:26 a.m. OK PyPy 3-64 TESTS 23 343 29593600
367000232 amigo123 D March 16, 2026, 4:11 p.m. OK PyPy 3-64 TESTS 23 343 30105600
367008564 SmartieBeast D March 16, 2026, 4:35 p.m. OK PyPy 3-64 TESTS 23 343 48332800
367004602 ryen_x7 D March 16, 2026, 4:23 p.m. OK PyPy 3-64 TESTS 23 343 52838400
367008601 BlackOutBit D March 16, 2026, 4:35 p.m. OK PyPy 3-64 TESTS 23 359 30105600
367013546 EgeeReyZee D March 16, 2026, 4:49 p.m. OK PyPy 3-64 TESTS 23 359 48128000
367008846 cruelagent47 D March 16, 2026, 4:35 p.m. OK PyPy 3-64 TESTS 23 359 48230400
367013783 Uttam_Masuram D March 16, 2026, 4:51 p.m. OK Python 3 TESTS 23 421 61644800
367006234 Satheesh_29 D March 16, 2026, 4:28 p.m. OK Python 3 TESTS 23 453 63283200
367009447 tuanduong D March 16, 2026, 4:37 p.m. OK Python 3 TESTS 23 484 45158400
367002901 megha_12c1 D March 16, 2026, 4:19 p.m. OK Python 3 TESTS 23 500 63283200
367005901 manimohamed D March 16, 2026, 4:27 p.m. OK Python 3 TESTS 23 515 61644800
367017280 alevtinka TarasovE D March 16, 2026, 5:17 p.m. OK Python 3 TESTS 23 531 65433600
367006288 yusikome D March 16, 2026, 4:28 p.m. OK Python 3 TESTS 23 546 37068800
367053028 quandum D March 17, 2026, 4:27 a.m. OK Python 3 TESTS 23 687 83046400
367001364 guweiz D March 16, 2026, 4:14 p.m. OK Python 3 TESTS 23 734 37273600
367005666 pillowprism D March 16, 2026, 4:26 p.m. OK Python 3 TESTS 23 734 88268800
367012163 sandcrawler D March 16, 2026, 4:46 p.m. OK Rust 2024 TESTS 23 109 16896000
367001863 mo0307b1006 D March 16, 2026, 4:16 p.m. OK Rust 2024 TESTS 23 125 24371200
367000958 _JG_ D March 16, 2026, 4:13 p.m. OK Rust 2024 TESTS 23 218 59904000

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