Submission #66767040

Source Code Expand

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from collections import deque
import sys
sys.setrecursionlimit(10**7)
N, M = map(int, input().split())
graph = {i: [] for i in range(N)}
for _ in range(M):
    u, v, w = map(int, input().split())
    graph[u-1].append((v-1, w))
d = [0] * N
visited = [False] * N
cycles = []
def dfs(u):
    visited[u] = True
    for v, w in graph[u]:
        x = d[u] ^ w
        if not visited[v]:
            d[v] = x
            dfs(v)
        else:
 
 
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from collections import deque
import sys
sys.setrecursionlimit(10**7)

N, M = map(int, input().split())
graph = {i: [] for i in range(N)}
for _ in range(M):
    u, v, w = map(int, input().split())
    graph[u-1].append((v-1, w))

d = [0] * N
visited = [False] * N
cycles = []
def dfs(u):
    visited[u] = True
    for v, w in graph[u]:
        x = d[u] ^ w
        if not visited[v]:
            d[v] = x
            dfs(v)
        else:
            cyc = x ^ d[v]
            if cyc:
                cycles.append(cyc)

dfs(0)
if not visited[N-1]:
    print(-1)
    exit()

def build_basis(xs):
    B = []
    for x in sorted(xs, reverse=True):
        for b in B:
            x = min(x, x ^ b)
        if x:
            B.append(x)
    return B

basis = build_basis(cycles)

res = d[N-1]
for b in basis:
    res = min(res, res ^ b)

print(res)

Submission Info

Judge Result