CSES - Aalto Competitive Programming 2026 - wk7 - Mon

Submission details
Task:	Road blockade
Sender:	aalto26gm_037
Submission time:	2026-10-19 17:39:01 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	WRONG ANSWER

Test results
test	verdict	time
#1	ACCEPTED	0.04 s	details
#2	ACCEPTED	0.04 s	details
#3	ACCEPTED	0.04 s	details
#4	WRONG ANSWER	0.04 s	details
#5	WRONG ANSWER	0.04 s	details
#6	WRONG ANSWER	0.04 s	details
#7	ACCEPTED	0.04 s	details
#8	ACCEPTED	0.04 s	details
#9	WRONG ANSWER	0.04 s	details
#10	WRONG ANSWER	0.04 s	details
#11	WRONG ANSWER	0.04 s	details
#12	WRONG ANSWER	0.04 s	details
#13	WRONG ANSWER	0.04 s	details
#14	WRONG ANSWER	0.04 s	details
#15	ACCEPTED	0.04 s	details
#16	ACCEPTED	0.04 s	details
#17	WRONG ANSWER	0.04 s	details
#18	WRONG ANSWER	0.04 s	details
#19	WRONG ANSWER	0.04 s	details
#20	WRONG ANSWER	0.04 s	details
#21	WRONG ANSWER	0.04 s	details
#22	ACCEPTED	0.04 s	details
#23	ACCEPTED	0.04 s	details
#24	WRONG ANSWER	0.04 s	details
#25	ACCEPTED	0.04 s	details
#26	ACCEPTED	0.04 s	details
#27	WRONG ANSWER	0.04 s	details
#28	WRONG ANSWER	0.04 s	details
#29	WRONG ANSWER	0.04 s	details
#30	ACCEPTED	0.04 s	details
#31	ACCEPTED	0.04 s	details
#32	ACCEPTED	0.04 s	details
#33	ACCEPTED	0.04 s	details
#34	ACCEPTED	0.04 s	details
#35	WRONG ANSWER	0.04 s	details
#36	ACCEPTED	0.04 s	details
#37	ACCEPTED	0.04 s	details
#38	WRONG ANSWER	0.04 s	details
#39	ACCEPTED	0.04 s	details
#40	ACCEPTED	0.04 s	details
#41	ACCEPTED	0.04 s	details
#42	WRONG ANSWER	0.04 s	details
#43	ACCEPTED	0.04 s	details
#44	ACCEPTED	0.04 s	details
#45	ACCEPTED	0.04 s	details
#46	ACCEPTED	0.04 s	details
#47	WRONG ANSWER	0.04 s	details
#48	WRONG ANSWER	0.04 s	details
#49	ACCEPTED	0.04 s	details
#50	ACCEPTED	0.06 s	details
#51	ACCEPTED	0.07 s	details
#52	ACCEPTED	0.08 s	details
#53	ACCEPTED	0.08 s	details
#54	ACCEPTED	0.06 s	details
#55	ACCEPTED	0.08 s	details
#56	ACCEPTED	0.06 s	details
#57	ACCEPTED	0.08 s	details
#58	WRONG ANSWER	0.08 s	details
#59	ACCEPTED	0.07 s	details
#60	ACCEPTED	0.32 s	details
#61	ACCEPTED	0.31 s	details
#62	WRONG ANSWER	0.43 s	details
#63	WRONG ANSWER	0.44 s	details
#64	ACCEPTED	0.31 s	details
#65	ACCEPTED	0.35 s	details
#66	ACCEPTED	0.31 s	details
#67	ACCEPTED	0.31 s	details
#68	ACCEPTED	0.50 s	details
#69	ACCEPTED	0.30 s	details

Code

n, m = map(int, input().split())

graph = [[] for _ in range(n + 1)]
for i in range(1, m + 1):
    a, b = map(int, input().split())
    graph[a].append((b, i))
    graph[b].append((a, i))

tin = [0] * (n + 1)
low = [0] * (n + 1)
parent = [0] * (n + 1)
parent_road = [0] * (n + 1)
pointer = [0] * (n + 1)

timer = 1
tin[1] = low[1] = 1
stack = [1]

while stack:
    v = stack[-1]
    if pointer[v] < len(graph[v]):
        to, road = graph[v][pointer[v]]
        pointer[v] += 1
        if road == parent_road[v]:
            continue
        if tin[to]:
            low[v] = min(low[v], tin[to])
        else:
            timer += 1
            tin[to] = low[to] = timer
            parent[to] = v
            parent_road[to] = road
            stack.append(to)
    else:
        stack.pop()

answer = 0
v = n
while v != 1:
    if low[v] > tin[parent[v]]:
        answer = parent_road[v]
    v = parent[v]

print(answer)

Test details

Test 1

Verdict: ACCEPTED

input
`2 1 1 2` view save

correct output
`1` view save

user output
`1` view save

Test 2

Verdict: ACCEPTED

input
`3 2 1 2 2 3` view save

correct output
`1` view save

user output
`1` view save

Test 3

Verdict: ACCEPTED

input
`3 2 2 3 1 2` view save

correct output
`2` view save

user output
`2` view save

Test 4

Verdict: WRONG ANSWER

input
`3 3 1 2 1 3 2 3` view save

correct output
`0` view save

user output
`1` view save

Test 5

Verdict: WRONG ANSWER

input
`4 6 1 3 1 4 2 4 2 3 ...` view save

correct output
`0` view save

user output
`1` view save

Test 6

Verdict: WRONG ANSWER

input
`4 4 1 3 2 3 3 4 1 2` view save

correct output
`3` view save

user output
`1` view save

Test 7

Verdict: ACCEPTED

input
`4 3 1 3 2 4 2 3` view save

correct output
`1` view save

user output
`1` view save

Test 8

Verdict: ACCEPTED

input
`4 3 2 3 2 4 1 3` view save

correct output
`3` view save

user output
`3` view save

Test 9

Verdict: WRONG ANSWER

input
`4 4 3 4 2 3 1 3 1 2` view save

correct output
`1` view save

user output
`3` view save

Test 10

Verdict: WRONG ANSWER

input
`5 7 2 5 3 5 3 4 1 5 ...` view save

correct output
`0` view save

user output
`4` view save

Test 11

Verdict: WRONG ANSWER

input
`5 10 3 4 1 5 1 4 1 2 ...` view save

correct output
`0` view save

user output
`2` view save

Test 12

Verdict: WRONG ANSWER

input
`5 6 1 4 3 4 4 5 2 3 ...` view save

correct output
`3` view save

user output
`1` view save

Test 13

Verdict: WRONG ANSWER

input
`5 5 3 5 1 4 1 5 2 3 ...` view save

correct output
`0` view save

user output
`2` view save

Test 14

Verdict: WRONG ANSWER

input
`5 7 2 4 1 5 3 5 2 5 ...` view save

correct output
`0` view save

user output
`2` view save

Test 15

Verdict: ACCEPTED

input
`5 4 1 3 2 3 2 4 4 5` view save

correct output
`1` view save

user output
`1` view save

Test 16

Verdict: ACCEPTED

input
`5 4 2 4 3 5 2 3 1 4` view save

correct output
`4` view save

user output
`4` view save

Test 17

Verdict: WRONG ANSWER

input
`5 9 4 5 1 2 3 4 1 5 ...` view save

correct output
`0` view save

user output
`2` view save

Test 18

Verdict: WRONG ANSWER

input
`5 10 1 3 2 5 4 5 3 4 ...` view save

correct output
`0` view save

user output
`1` view save

Test 19

Verdict: WRONG ANSWER

input
`5 7 1 3 1 2 4 5 2 4 ...` view save

correct output
`0` view save

user output
`1` view save

Test 20

Verdict: WRONG ANSWER

input
`10 12 2 5 4 9 4 7 3 9 ...` view save

correct output
`9` view save

user output
`5` view save

Test 21

Verdict: WRONG ANSWER

input
`10 43 7 10 1 2 1 3 2 3 ...` view save

correct output
`0` view save

user output
`2` view save

Test 22

Verdict: ACCEPTED

input
`10 11 2 5 2 3 6 7 1 2 ...` view save

correct output
`4` view save

user output
`4` view save

Test 23

Verdict: ACCEPTED

input
`10 10 4 9 5 9 7 8 6 8 ...` view save

correct output
`8` view save

user output
`8` view save

Test 24

Verdict: WRONG ANSWER

input
`10 12 7 9 3 8 3 5 4 5 ...` view save

correct output
`0` view save

user output
`6` view save

Test 25

Verdict: ACCEPTED

input
`10 9 2 4 8 10 6 7 2 3 ...` view save

correct output
`9` view save

user output
`9` view save

Test 26

Verdict: ACCEPTED

input
`10 9 3 5 5 7 1 6 4 6 ...` view save

correct output
`3` view save

user output
`3` view save

Test 27

Verdict: WRONG ANSWER

input
`10 37 5 9 3 4 1 4 7 10 ...` view save

correct output
`0` view save

user output
`3` view save

Test 28

Verdict: WRONG ANSWER

input
`10 44 2 6 1 2 1 6 4 7 ...` view save

correct output
`0` view save

user output
`2` view save

Test 29

Verdict: WRONG ANSWER

input
`10 27 1 10 7 10 4 7 2 9 ...` view save

correct output
`0` view save

user output
`1` view save

Test 30

Verdict: ACCEPTED

input
`100 107 44 59 24 76 35 79 14 57 ...` view save

correct output
`107` view save

user output
`107` view save

Test 31

Verdict: ACCEPTED

input
`100 107 27 79 43 89 83 96 34 75 ...` view save

correct output
`42` view save

user output
`42` view save

Test 32

Verdict: ACCEPTED

input
`100 143 13 14 20 59 25 95 38 84 ...` view save

correct output
`129` view save

user output
`129` view save

Test 33

Verdict: ACCEPTED

input
`100 155 29 92 3 63 16 18 9 28 ...` view save

correct output
`36` view save

user output
`36` view save

Test 34

Verdict: ACCEPTED

input
`100 105 74 85 6 49 7 81 45 55 ...` view save

correct output
`50` view save

user output
`50` view save

Test 35

Verdict: WRONG ANSWER

input
`100 121 8 74 14 50 44 55 12 93 ...` view save

correct output
`0` view save

user output
`16` view save

Test 36

Verdict: ACCEPTED

input
`100 102 54 97 45 82 30 78 40 44 ...` view save

correct output
`35` view save

user output
`35` view save

Test 37

Verdict: ACCEPTED

input
`100 106 57 85 3 58 14 93 31 61 ...` view save

correct output
`8` view save

user output
`8` view save

Test 38

Verdict: WRONG ANSWER

input
`100 188 3 58 53 63 8 19 97 100 ...` view save

correct output
`0` view save

user output
`51` view save

Test 39

Verdict: ACCEPTED

input
`100 100 16 94 48 96 4 37 71 85 ...` view save

correct output
`41` view save

user output
`41` view save

Test 40

Verdict: ACCEPTED

input
`200 207 111 188 80 121 115 170 157 175 ...` view save

correct output
`199` view save

user output
`199` view save

Test 41

Verdict: ACCEPTED

input
`200 207 99 117 139 143 151 174 136 184 ...` view save

correct output
`190` view save

user output
`190` view save

Test 42

Verdict: WRONG ANSWER

input
`200 287 36 180 125 138 33 147 38 188 ...` view save

correct output
`77` view save

user output
`13` view save

Test 43

Verdict: ACCEPTED

input
`200 310 162 195 21 199 95 180 29 127 ...` view save

correct output
`30` view save

user output
`30` view save

Test 44

Verdict: ACCEPTED

input
`200 205 140 187 127 185 100 196 55 144 ...` view save

correct output
`150` view save

user output
`150` view save

Test 45

Verdict: ACCEPTED

input
`200 243 8 85 73 137 52 72 51 157 ...` view save

correct output
`53` view save

user output
`53` view save

Test 46

Verdict: ACCEPTED

input
`200 202 45 72 5 96 1 31 35 187 ...` view save

correct output
`3` view save

user output
`3` view save

Test 47

Verdict: WRONG ANSWER

input
`200 214 81 116 113 164 154 199 17 153 ...` view save

correct output
`45` view save

user output
`34` view save

Test 48

Verdict: WRONG ANSWER

input
`200 375 68 93 93 101 87 109 23 56 ...` view save

correct output
`0` view save

user output
`17` view save

Test 49

Verdict: ACCEPTED

input
`200 201 64 124 145 164 103 127 126 186 ...` view save

correct output
`137` view save

user output
`137` view save

Test 50

Verdict: ACCEPTED

input
`1000 1007 61 967 252 530 105 953 490 826 ...` view save

correct output
`914` view save

user output
`914` view save

Test 51

Verdict: ACCEPTED

input
`1000 1007 489 976 53 720 478 732 104 111 ...` view save

correct output
`248` view save

user output
`248` view save

Test 52

Verdict: ACCEPTED

input
`1000 1435 520 551 702 787 76 719 619 993 ...` view save

correct output
`1114` view save

user output
`1114` view save

Test 53

Verdict: ACCEPTED

input
`1000 1550 206 315 476 801 287 713 456 677 ...` view save

correct output
`1059` view save

user output
`1059` view save

Test 54

Verdict: ACCEPTED

input
`1000 1005 304 771 84 930 17 988 282 364 ...` view save

correct output
`714` view save

user output
`714` view save

Test 55

Verdict: ACCEPTED

input
`1000 1221 254 729 301 692 201 239 530 550 ...` view save

correct output
`406` view save

user output
`406` view save

Test 56

Verdict: ACCEPTED

input
`1000 1002 147 586 502 522 194 372 176 451 ...` view save

correct output
`117` view save

user output
`117` view save

Test 57

Verdict: ACCEPTED

input
`1000 1075 470 600 129 251 654 850 567 661 ...` view save

correct output
`642` view save

user output
`642` view save

Test 58

Verdict: WRONG ANSWER

input
`1000 1874 668 731 316 335 532 731 523 839 ...` view save

correct output
`0` view save

user output
`493` view save

Test 59

Verdict: ACCEPTED

input
`1000 1009 674 739 96 435 360 670 130 773 ...` view save

correct output
`768` view save

user output
`768` view save

Test 60

Verdict: ACCEPTED

input
`100000 100007 44087 69715 31775 43251 18923 35874 36912 75163 ...` view save

correct output
`923` view save

user output
`923` view save

Test 61

Verdict: ACCEPTED

input
`100000 100007 19253 34700 66338 83144 22343 27898 4199 35494 ...` view save

correct output
`9842` view save

user output
`9842` view save

Test 62

Verdict: WRONG ANSWER

input
`100000 143600 14018 46297 31183 86763 34508 87502 54400 64922 ...` view save

correct output
`0` view save

user output
`7826` view save

Test 63

Verdict: WRONG ANSWER

input
`100000 155080 7038 29509 13361 87647 1940 92912 7785 12866 ...` view save

correct output
`0` view save

user output
`35157` view save

Test 64

Verdict: ACCEPTED

input
`100000 100005 33360 89287 42922 67061 77709 78585 48488 51346 ...` view save

correct output
`523` view save

user output
`523` view save

Test 65

Verdict: ACCEPTED

input
`100000 122199 24155 82039 27201 64021 37961 66619 7615 11277 ...` view save

correct output
`61740` view save

user output
`61740` view save

Test 66

Verdict: ACCEPTED

input
`100000 100002 13135 96454 53655 77933 52027 71763 40622 57175 ...` view save

correct output
`60082` view save

user output
`60082` view save

Test 67

Verdict: ACCEPTED

input
`100000 107630 30498 57903 5372 70239 51740 59293 41709 92770 ...` view save

correct output
`102920` view save

user output
`102920` view save

Test 68

Verdict: ACCEPTED

input
`100000 187345 5859 71722 58010 74508 66929 91927 15925 53657 ...` view save

correct output
`129660` view save

user output
`129660` view save

Test 69

Verdict: ACCEPTED

input
`100000 101036 13541 29328 50426 75396 46089 77950 42830 56873 ...` view save

correct output
`80466` view save

user output
`80466` view save

Aalto Competitive Programming 2026 - wk7 - Mon

Road blockade

Code

Test details

Test 1

Test 2

Test 3

Test 4

Test 5

Test 6

Test 7

Test 8

Test 9

Test 10

Test 11

Test 12

Test 13

Test 14

Test 15

Test 16

Test 17

Test 18

Test 19

Test 20

Test 21

Test 22

Test 23

Test 24

Test 25

Test 26

Test 27

Test 28

Test 29

Test 30

Test 31

Test 32

Test 33

Test 34

Test 35

Test 36

Test 37

Test 38

Test 39

Test 40

Test 41

Test 42

Test 43

Test 44

Test 45

Test 46

Test 47

Test 48

Test 49

Test 50

Test 51

Test 52

Test 53

Test 54

Test 55

Test 56

Test 57

Test 58

Test 59

Test 60

Test 61

Test 62

Test 63

Test 64

Test 65

Test 66

Test 67

Test 68

Test 69

Tasks

Submissions (aalto26gm_037)