union find木の実装

前提

今union find木の勉強をしているのですが、コード自体は蟻本に書いているものをそのままパクってきたのですが、なぜかエラーが出ます。

発生している問題・エラーメッセージ

./Main.cpp: In function ‘void init(int)’: ./Main.cpp:10:12: error: reference to ‘rank’ is ambiguous 10 | rank[i] = 0; | ^~~~ In file included from /usr/include/c++/9/bits/move.h:55, from /usr/include/c++/9/bits/nested_exception.h:40, from /usr/include/c++/9/exception:144, from /usr/include/c++/9/ios:39, from /usr/include/c++/9/ostream:38, from /usr/include/c++/9/iostream:39, from ./Main.cpp:1: /usr/include/c++/9/type_traits:1257:12: note: candidates are: ‘template<class> struct std::rank’ 1257 | struct rank | ^~~~ ./Main.cpp:6:15: note: ‘std::vector<int> rank’ 6 | vector<int>rank(MAX_int); | ^~~~ ./Main.cpp: In function ‘void unite(int, int)’: ./Main.cpp:19:11: error: reference to ‘rank’ is ambiguous 19 | if(rank[x] <rank[y])par[x] == y; | ^~~~ In file included from /usr/include/c++/9/bits/move.h:55, from /usr/include/c++/9/bits/nested_exception.h:40, from /usr/include/c++/9/exception:144, from /usr/include/c++/9/ios:39, from /usr/include/c++/9/ostream:38, from /usr/include/c++/9/iostream:39, from ./Main.cpp:1: /usr/include/c++/9/type_traits:1257:12: note: candidates are: ‘template<class> struct std::rank’ 1257 | struct rank | ^~~~ ./Main.cpp:6:15: note: ‘std::vector<int> rank’ 6 | vector<int>rank(MAX_int); | ^~~~ ./Main.cpp:19:20: error: reference to ‘rank’ is ambiguous 19 | if(rank[x] <rank[y])par[x] == y; | ^~~~ In file included from /usr/include/c++/9/bits/move.h:55, from /usr/include/c++/9/bits/nested_exception.h:40, from /usr/include/c++/9/exception:144, from /usr/include/c++/9/ios:39, f...

該当のソースコード

c++

#include <iostream>#include<vector>using namespace std;static const int MAX_int = 100000000; vector<int>par(MAX_int); vector<int>rank(MAX_int); void init(int n){ for(int i=0;i<n;i++){ par[i] = i; rank[i] = 0; } } int find(int x){ if(par[x] == x)return x; else return par[x] == find(par[x]); } void unite(int x,int y){ x = find(x);y = find(y);if(y == x)return; if(rank[x] <rank[y])par[x] == y; else { par[y] == x; if(rank[x] == rank[y])rank[x]++; } } bool same(int x,int y){ return find[x] == find[y]; }int main(void){ int N,M;cin >> N >> M; vector<pair<int,int>>a(M); for(int i=0;i<M;i++){ cin >> a[i].first >> a[i].second; } map<int,int>b; for(int i=0;i<M;i++){ b[a[i].first-1]++;b[a[i].second-1]++; } bool ans = false; for(int i=0;i<M;i++){ if(same(a[i].first ,a[i].second))ans = true; unite(a[i].first,a[i].second); } for(int i = 0;i<N;i++){ if(b[i] > 2 || ans){ cout << "No" << endl;return 0; } } cout << "Yes" << endl;}

試したこと

補足情報（FW/ツールのバージョンなど）

int関数の中は無視してください。