Submission #27860233

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Source Code Expand

#include <bits/stdc++.h>
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define rep2(i,k,n) for (int i = (k); i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;
// using P = pair<ll,ll>;

const ll INF = (ll)1e18;
// const int INF = (int)1e9+7;
template<typename T>
void chmin(T &a, T b) { a = min(a, b); }
template<typename T>
void chmax(T &a, T b) { a = max(a, b); }

using Graph = vector<vector<int>>;

typedef struct Node {
    int now, prev;
};

bool hasCycle(Graph &graph) {
    int n = graph.size();
    vector<int> used(n,0);
    rep(i,n) {
        if (used[i]) continue;
        queue<Node> que;
        que.push({i,-1});
        while(!que.empty()) {
            Node node = que.front();
            que.pop();
            if (used[node.now]) {
                return true;
            }
            used[node.now] = true;
            for (int x : graph[node.now]) {
                if (x == node.prev) continue;
                que.push({x,node.now});
            }
        }
    }
    return false;
}

void solve() {
    int n, m;
    cin >> n >> m;

    Graph graph(n);
    rep(i,m) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }

    rep(i,n) {
        if (graph[i].size() > 2) {
            cout << "No" << endl;
            return;
        }
    }

    if (hasCycle(graph)) {
        cout << "No" << endl;
        return;
    }

    cout << "Yes" << endl;
}

int main() {
    solve();
    return 0;
}

Submission Info

Compile Error

./Main.cpp:20:1: warning: ‘typedef’ was ignored in this declaration
   20 | typedef struct Node {
      | ^~~~~~~

Judge Result