CSES - Aalto Competitive Programming 2025 - wk7 - Wed

Submission details
Task:	Airport
Sender:	aalto25h_003
Submission time:	2025-10-22 17:45:28 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	RUNTIME ERROR

Test results
test	verdict	time
#1	RUNTIME ERROR	0.07 s	details
#2	RUNTIME ERROR	0.07 s	details
#3	RUNTIME ERROR	0.07 s	details
#4	RUNTIME ERROR	0.07 s	details
#5	RUNTIME ERROR	0.07 s	details
#6	RUNTIME ERROR	0.09 s	details
#7	RUNTIME ERROR	0.09 s	details
#8	RUNTIME ERROR	0.09 s	details
#9	RUNTIME ERROR	0.09 s	details
#10	RUNTIME ERROR	0.09 s	details
#11	RUNTIME ERROR	0.07 s	details
#12	RUNTIME ERROR	0.07 s	details
#13	RUNTIME ERROR	0.07 s	details

Code

from collections import defaultdict, deque

def airport():
    n, m = map(int, input().split())

    checkpoint_capacity = list(map(int, input().split()))
    
    graph = defaultdict(lambda: defaultdict(int))
 
    for i in range(n):
        if checkpoint_capacity[i] == -1:
            graph[2*i+1][2*i+2] = float('inf')
        else:
            graph[2*i+1][2*i+2] = checkpoint_capacity[i]
    
    for _ in range(m):
        a, b = map(int, input().split())
        graph[2*a][2*b-1] = float('inf')
    
    def find_path(source, sink, parent):
        visited = set([source])
        queue = deque([source])

        while queue:
            u = queue.popleft()
            for v in graph[u]:
                if v not in visited and graph[u][v] > 0:
                    visited.add(v)
                    parent[v] = u
                    queue.append(v)

                    if v == sink:
                        return True
        return False

    max_flow = 0
    source = 1
    sink = 2*n
    while True:
        parent = {}
        if not find_path(source, sink, parent):
            break
        v = sink
        while v != source:
            u = parent[v]
            path_flow = min(path_flow, graph[u][v])
            v = u
        v = sink
        while v != source:
            u = parent[v]
            graph[u][v] -= path_flow
            graph[v][u] += path_flow
            v = u
        max_flow += path_flow
    print(max_flow)

if __name__ == "__main__":
    airport()

Test details

Test 1

Verdict: RUNTIME ERROR

input
`10 20 -1 85 7 19 90 72 11 46 65 -1 6 7 9 7 8 4 ...` view save

correct output
`7` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 2

Verdict: RUNTIME ERROR

input
`10 20 -1 80 77 57 77 95 63 98 30 -1 6 7 8 9 7 8 ...` view save

correct output
`30` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 3

Verdict: RUNTIME ERROR

input
`10 20 -1 63 16 42 62 70 9 94 68 -1 10 9 6 8 10 6 ...` view save

correct output
`25` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 4

Verdict: RUNTIME ERROR

input
`10 20 -1 3 86 -1 32 34 9 50 -1 -1 6 7 7 8 9 2 ...` view save

correct output
`3` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 5

Verdict: RUNTIME ERROR

input
`10 20 -1 43 38 -1 7 54 26 97 76 -1 3 9 9 10 6 7 ...` view save

correct output
`76` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 6

Verdict: RUNTIME ERROR

input
`100 1000 -1 425576195 274150382 1021768...` view save

correct output
`6091126630` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 7

Verdict: RUNTIME ERROR

input
`100 1000 -1 769953265 -1 389517741 2323...` view save

correct output
`769953265` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 8

Verdict: RUNTIME ERROR

input
`100 1000 -1 584988267 763129662 6781413...` view save

correct output
`1699511766` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 9

Verdict: RUNTIME ERROR

input
`100 1000 -1 921671366 121044688 2933366...` view save

correct output
`1805833567` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 10

Verdict: RUNTIME ERROR

input
`100 1000 -1 763842763 612011030 4532521...` view save

correct output
`3342235784` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 11

Verdict: RUNTIME ERROR

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

correct output
`1` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 12

Verdict: RUNTIME ERROR

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

correct output
`1` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Test 13

Verdict: RUNTIME ERROR

input
`7 8 -1 1 1 1 1 1 -1 1 2 1 3 2 4 ...` view save

correct output
`1` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "input/code.py", line 58, in <module>
    airport()
  File "input/code.py", line 46, in airport
    path_flow = min(path_flow, graph[u][v])
UnboundLocalError: local variable 'path_flow' referenced before assignment

Aalto Competitive Programming 2025 - wk7 - Wed

Airport

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

Tasks

Submissions (aalto25h_003)