Submission details
Task:Connect cities
Sender:aalto26bh_025
Submission time:2026-09-05 21:02:03 +0300
Language:Python3 (PyPy3)
Status:READY
Result:
Test results
testverdicttime
#1ACCEPTED0.04 sdetails
#2ACCEPTED0.04 sdetails
#3ACCEPTED0.04 sdetails
#4ACCEPTED0.04 sdetails
#5ACCEPTED0.04 sdetails
#6--details
#7--details
#8--details
#9--details
#10--details
#11--details
#12ACCEPTED0.04 sdetails

Code

# Dictionary for speed.
builtRoads = {}

## Get adjecent cities of a city.
def getAdjecent(city: int) -> list[int]:
    return builtRoads.get(city, [])
 
def getGroupings(cities: int) -> list[list[int]]:
    ## Store groupings
    cityGroupings = []
 
    # Store unchecked cities
    uncheckedCities = []
    for i in range(1, cities + 1):
        uncheckedCities.append(i)
 
    # While we have cities to check.
    while(len(uncheckedCities) != 0):
        # Ini
        current = uncheckedCities[0]
        visited = []
        yetToVisit = getAdjecent(current)
 
        # If this city is alone, just add it to list.
        if(len(yetToVisit) == 0):
            visited.append(current)
 
        while(len(yetToVisit) != 0):
 
            # Append current city and change it.
            visited.append(current)
            current = yetToVisit[0]
 
            # remove current one.
            yetToVisit.pop(0)
 
            # Add new adjecent cities that we have not been to.
            for n in getAdjecent(current):
                if n not in visited and n not in yetToVisit:
                    yetToVisit.append(n)
 
        # Last one
        if current not in visited:
            visited.append(current)
        
        cityGroupings.append(visited)
 
        # Remove all of these cities from unchecked.
        for city in visited:
            if city in uncheckedCities:
                uncheckedCities.remove(city)
 
    return cityGroupings
 
 
 
# Read input
read = input().split(" ")
cityCount = int(read[0])
roadCount = int(read[1])
 
# Read list of roads
for i in range(0, roadCount):
    a, b = map(int, input().split(" "))

    # Ini dict for speed.
    if a not in builtRoads: builtRoads[a] = []
    builtRoads[a].append(b)
    if b not in builtRoads: builtRoads[b] = []
    builtRoads[b].append(a)
 
# Figure out groupings.
# Array of cities grouped on their connectivity.
groupedCityArray = getGroupings(cityCount)
 
# Array of needed roads
neededRoadArray = []
 
# Add a new path that connects groups. Use first node in group.
## Basically just create a circle, where the last two are not connected.
for i in range(0, len(groupedCityArray) - 1):
    neededRoadArray.append([groupedCityArray[i][0], groupedCityArray[i + 1][0]])
 
# Output
print(len(neededRoadArray))
for i in neededRoadArray:
    print(str(i[0])+" "+str(i[1]))

Test details

Test 1

Verdict: ACCEPTED

input
10 10
2 5
5 6
1 4
6 8
...

correct output
2
1 2
2 7

user output
2
1 2
2 7

Test 2

Verdict: ACCEPTED

input
10 10
3 9
6 8
9 10
7 8
...

correct output
2
1 4
4 5

user output
2
1 4
4 5

Test 3

Verdict: ACCEPTED

input
10 10
7 9
1 7
1 3
3 4
...

correct output
0

user output
0

Test 4

Verdict: ACCEPTED

input
10 10
4 8
5 9
4 9
2 7
...

correct output
1
1 3

user output
1
1 3

Test 5

Verdict: ACCEPTED

input
10 10
4 9
2 4
7 10
1 8
...

correct output
0

user output
0

Test 6

Verdict:

input
100000 200000
7233 22146
94937 96203
6133 10731
98737 99193
...

correct output
4785
1 2
2 3
3 4
4 5
...

user output
(empty)

Test 7

Verdict:

input
100000 200000
92950 93575
24401 88897
41796 99364
47106 50330
...

correct output
4868
1 2
2 7
7 9
9 15
...

user output
(empty)

Test 8

Verdict:

input
100000 200000
15637 76736
79169 98809
4382 86557
73383 77029
...

correct output
4683
1 9
9 20
20 27
27 28
...

user output
(empty)

Test 9

Verdict:

input
100000 200000
47932 66981
86401 99942
4353 27841
60492 67345
...

correct output
4807
1 6
6 7
7 11
11 12
...

user output
(empty)

Test 10

Verdict:

input
100000 200000
6554 44548
76413 98555
5447 59589
70166 74434
...

correct output
4786
1 2
2 18
18 21
21 27
...

user output
(empty)

Test 11

Verdict:

input
100000 1
1 2

correct output
99998
1 3
3 4
4 5
5 6
...

user output
(empty)

Test 12

Verdict: ACCEPTED

input
10 9
2 5
5 6
1 4
6 8
...

correct output
2
1 2
2 7

user output
2
1 2
2 7