diff --git "a/khj20006/202511/30 BOJ P5 \354\246\211\355\235\245 \354\227\254\355\226\211 (Easy).md" "b/khj20006/202511/30 BOJ P5 \354\246\211\355\235\245 \354\227\254\355\226\211 (Easy).md" new file mode 100644 index 00000000..f468354b --- /dev/null +++ "b/khj20006/202511/30 BOJ P5 \354\246\211\355\235\245 \354\227\254\355\226\211 (Easy).md" @@ -0,0 +1,47 @@ +```cpp +#include +using namespace std; + +int N, M; +vector> G(200001), R(200001); +bitset<200001> vis; +int last, cnt = 0; + +void dfs1(int n) { + for (int i : G[n]) if (!vis[i]) { + vis[i] = 1; + dfs1(i); + } + last = n; +} + +void dfs2(int n) { + cnt++; + for (int i : R[n]) if (!vis[i]) { + vis[i] = 1; + dfs2(i); + } +} + +int main() { + cin.tie(0)->sync_with_stdio(0); + + cin >> N >> M; + for (int a, b; M--;) { + cin >> a >> b; + G[a].push_back(b); + R[b].push_back(a); + } + + for (int i = 1; i <= N; i++) if (!vis[i]) { + vis[i] = 1; + dfs1(i); + } + + vis.reset(); + vis[last] = 1; + dfs2(last); + cout << (cnt == N ? "Yes" : "No"); + +} +```