CSES - Aalto Competitive Programming 2024 - wk4 - Mon - Results
Submission details
Task:Forest density
Sender:Spot
Submission time:2024-09-23 17:07:12 +0300
Language:Python3 (PyPy3)
Status:READY
Result:
Test results
testverdicttime
#10.04 sdetails
#20.66 sdetails
#30.61 sdetails

Code

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

# Create grid and prefix sum array
forest = [list(input()) for i in range(n)]

print("forest:", forest)

# Prefix sum array
prefix = [[0] * (n + 1) for _ in range(n + 1)]

print("prefix:", prefix)

# Build prefix sum array
for i in range(1, n + 1):
    for j in range(1, n + 1):
        # Check if there is a tree
        tree = 1 if forest[i - 1][j - 1] == "*" else 0
        prefix[i][j] = tree + prefix[i - 1][j] + prefix[i][j - 1] - prefix[i - 1][j - 1]

# Process queries
results = []
for i in range(q):
    y1, x1, y2, x2 = map(int, input().split())
    # Inclusion-exclusion principle to get the num of trees in rectangle
    result = (prefix[y2][x2]
              - prefix[y1 - 1][x2]
              - prefix[y2][x1 - 1]
              + prefix[y1 - 1][x1 - 1])
    results.append(result)

# Output all the results at once
print("\n".join(map(str, results)))

Test details

Test 1

Verdict:

input
10 100
**.*.*.**.
*.**.*..*.
.*****.**.
**....***.
...

correct output
10
14
5
7
8
...

user output
forest: [['*', '*', '.', '*', ...
Truncated

Test 2

Verdict:

input
1000 200000
**.**.****..**.***..**.***.**....

correct output
41079
2824
15631
1548
8483
...

user output
forest: [['*', '*', '.', '*', ...
Truncated

Test 3

Verdict:

input
1000 200000
******************************...

correct output
1000000
1000000
1000000
1000000
1000000
...

user output
forest: [['*', '*', '*', '*', ...
Truncated