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Crab Graphs.py
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Crab Graphs.py
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from collections import defaultdict, deque
def breadth_first_search(G, P, S, T, N):
V = defaultdict(int)
Q = deque([S])
V[S] += 1
P[S] = -1
while Q:
u = Q.popleft()
for v in range(N):
if V[v] == 0 and G[u][v] > 0:
Q.append(v)
P[v] = u
V[v] += 1
return V[T] == 1
def floyd_fulkerson(G, S, T, N):
P = [0 for _ in range(N)]
M = 0
while breadth_first_search(G, P, S, T, N):
F = float('inf')
v = T
while v != S:
u = P[v]
F = min(F, G[u][v])
v = P[v]
v = T
while v != S:
u = P[v]
G[u][v] -= F
G[v][u] += F
v = P[v]
M += F
return M
def main():
T = int(input())
for _ in range(T):
N, T, M = [int(i) for i in input().split()]
E = [[0 for _ in range((2 * N) + 2)] for _ in range((2 * N) + 2)]
for _ in range(M):
a, b = [int(i) for i in input().split()]
E[(2 * a)][(2 * b) + 1] = 1
E[(2 * b)][(2 * a) + 1] = 1
for n in range(1, N + 1):
E[0][(2 * n)] = T
E[(2 * n) + 1][1] = 1
print(floyd_fulkerson(E, 0, 1, (2 * N) + 2))
if __name__ == "__main__":
main()