ps | |
---|---|
링크 | acmicpc.net/… |
출처 | BOJ |
문제 번호 | 3860 |
문제명 | 할로윈 묘지 |
레벨 | 플래티넘 5 |
분류 |
SPFA |
시간복잡도 | O(W^2*H^2) |
인풋사이즈 | W<=30, H<=30 |
사용한 언어 | Python |
제출기록 | 35132KB / 1452ms |
최고기록 | 624ms |
해결날짜 | 2021/09/23 |
"""Solution code for "BOJ 3860. 할로윈 묘지".
- Problem link: https://www.acmicpc.net/problem/3860
- Solution link: http://www.teferi.net/ps/problems/boj/3860
Tags: [SPFA]
"""
import sys
from teflib import tgraph
INF = float('inf')
def main():
while True:
W, H = [int(x) for x in sys.stdin.readline().split()]
if W == H == 0:
break
G = int(sys.stdin.readline())
graves = set()
for _ in range(G):
X, Y = [int(x) for x in sys.stdin.readline().split()]
graves.add(Y * W + X)
wgraph = [{} for _ in range(W * H)]
E = int(sys.stdin.readline())
for _ in range(E):
X1, Y1, X2, Y2, T = [int(x) for x in sys.stdin.readline().split()]
source, dest = Y1 * W + X1, Y2 * W + X2
wgraph[source][dest] = T
for source, edges in enumerate(wgraph):
if wgraph[source]: # haunted hole exists
continue
y, x = divmod(source, W)
for dx, dy in [(-1, 0), (0, -1), (1, 0), (0, 1)]:
nx, ny = x + dx, y + dy
dest = ny * W + nx
if 0 <= nx < W and 0 <= ny < H and dest not in graves:
edges[dest] = 1
wgraph[W * H - 1].clear()
dists = tgraph.spfa(wgraph, 0)
if -INF in dists:
print('Never')
else:
dist_to_dest = dists[W * H - 1]
print('Impossible' if dist_to_dest == INF else dist_to_dest)
if __name__ == '__main__':
main()