lib/classes/unionfind.cpp

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• Last update: 2019-11-30 20:08:52+09:00

Verified with

• verify/unionfind.test.cpp

Code

struct UnionFind{
    vector<int> par;
    int count;
    UnionFind(int n) : par(n, -1), count(0){}
    int Find(int x){return par[x] < 0 ? x : Find(par[x]);}
    int Size(int x){return par[x] < 0 ? -par[x] : Size(par[x]);}
    bool Unite(int x, int y){
        x = Find(x);
        y = Find(y);
        if(x == y)
            return false;
        if(par[x] > par[y])
            swap(x, y);
        par[x] += par[y];
        par[y] = x;
        return ++count;
    }
};

#line 1 "lib/classes/unionfind.cpp"
struct UnionFind{
    vector<int> par;
    int count;
    UnionFind(int n) : par(n, -1), count(0){}
    int Find(int x){return par[x] < 0 ? x : Find(par[x]);}
    int Size(int x){return par[x] < 0 ? -par[x] : Size(par[x]);}
    bool Unite(int x, int y){
        x = Find(x);
        y = Find(y);
        if(x == y)
            return false;
        if(par[x] > par[y])
            swap(x, y);
        par[x] += par[y];
        par[y] = x;
        return ++count;
    }
};

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