Airport

class MaximumFlow:
    def __init__(self, nodes):
        self.nodes = nodes
        self.graph = {}
        for i in self.nodes:
            for j in self.nodes:
                self.graph[(i, j)] = 0

    def add_edge(self, node_a, node_b, capacity):
        self.graph[(node_a, node_b)] += capacity

    def add_flow(self, node, sink, flow):
        if node in self.seen:
            return 0
        self.seen.add(node)
        if node == sink:
            return flow
        for next_node in self.nodes:
            if self.flow[(node, next_node)] > 0:
                new_flow = min(flow, self.flow[(node, next_node)])
                inc = self.add_flow(next_node, sink, new_flow)
                if inc > 0:
                    self.flow[(node, next_node)] -= inc
                    self.flow[(next_node, node)] += inc
                    return inc
        return 0

    def construct(self, source, sink):
        self.flow = self.graph.copy()
        total = 0
        while True:
            self.seen = set()
            add = self.add_flow(source, sink, float("inf"))
            if add == 0:
                break
            total += add
        return total

n, m = map(int, input().split())
l = list(map(int, input().split()))
size = 2*n
M = MaximumFlow(range(size))
for i in range(n):
    if i == 0 or i == n - 1:
        continue
    cap = l[i]
    if cap == -1:
        cap = 10**9
    M.add_edge(i, i + n, cap)
for _ in range(m):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    if a == 0:
        from_node = 0
    else:
        from_node = a + n
    if b == n - 1:
        to_node = n - 1
    else:
        to_node = b
    M.add_edge(from_node, to_node, 10**9)


print(M.construct(0, n - 1))

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED