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#include <iostream>
#include <vector>
#include <numeric>

struct DSU {
    std::vector<int> size;
    std::vector<int> parent;
    int count;
    
    DSU(int n) {
        size.resize(n, 1);
        parent.resize(n);
        std::iota(parent.begin(), parent.end(), 0);
        count = n;
    }
    
    int find(int i) {
        if (parent[i] == i) {
            return i;
        }
        parent[i] = find(parent[i]);
        return parent[i];
    }
    
    void unite(int i, int j) {
        int ii = find(i);
        int jj = find(j);
        if (ii != jj) {
            --count;
            if (size[ii] < size[jj]) {
                std::swap(ii, jj);
            }
            parent[jj] = ii;
            size[ii] += size[jj];
        }
    }
};

class Solution {
public:
    int findCircleNum(vector<vector<int>>& isConnected) {
        int n = isConnected.size();
        DSU dsu(n);
        for (int i = 0; i < n - 1; ++i) {
            for (int j = i + 1; j < n; ++j) {
                if (isConnected[i][j] == 1) {
                    dsu.unite(i, j);
                }
            }
        }
        return dsu.count;
    }
};