Submission #8392573

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Source Code Expand

N, M = map(int, input().split())

p = list(map(int, input().split()))

class UnionFind():
    def __init__(self, n):
        self.par = [i for i in range(n)]
        self.rank = [0 for i in range(n)]

    def find(self, x):
        if self.par[x] == x:
            return x
        self.par[x] = self.find(self.par[x])
        return self.par[x]

    def unite(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return
        if self.rank[x] < self.rank[y]:
            self.par[x] = y
        elif self.rank[y] < self.rank[x]:
            self.par[y] = x
        else:
            self.rank[y] += 1
            self.par[x] = y
        

uf = UnionFind(N)

for i in range(M):
    x, y = map(int, input().split())
    uf.unite(x-1, y-1)

ans = 0
for i in range(N):
    if uf.find(p[i]-1) == uf.find(i):
        ans += 1

print(ans)

Submission Info

Judge Result