add atc_abc291_ex

test/atc_abc291_ex.cpp

@@ -0,0 +1,42 @@
+// competitive-verifier: PROBLEM https://atcoder.jp/contests/abc291/tasks/abc291_h
+
+#ifndef call_include
+#define call_include
+#include <bits/stdc++.h>
+using namespace std;
+#endif
+
+#include "graph/centroid_decomposition.cpp"
+
+int main() {
+	int N;
+	v2d<int> E;
+	vector<int> ans;
+
+	cin >> N;
+	for(int i = 0; i < N - 1; i++) {
+		int a, b;
+		cin >> a >> b;
+		a--, b--;
+		E[a].emplace_back(b);
+		E[b].emplace_back(a);
+	}
+	ans.resize(N);
+
+	auto cd = centroid_decomposition(E);
+	queue<tuple<int, int, int>> q;
+	q.emplace(0, N, -1);
+	while(not q.empty()) {
+		auto [x, xs, par] = q.front();
+		q.pop();
+
+		auto [cent, v] = cd.get(x, xs);
+		ans[cent] = par;
+		cd.del(cent);
+		for(int i = 0; i < v.size(); i++) {
+			q.emplace(v[i].first, v[i].second, cent + 1);
+		}
+	}
+
+	for(int i = 0; i < N; i++) cout << ans[i] << (i == N - 1 ? '\n' : ' ');
+}