D - Black and White Tree

https://atcoder.jp/contests/agc014/submissions/26377341

AtCoder/AGC014/D/D.cpp

@@ -0,0 +1,33 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, u, v;
+vector<int> g[100005];
+bool flag, vis[100005];
+
+void dfs(int u, int f) {
+    if (flag) return;
+    for (int i : g[u]) {
+        if (i != f) dfs(i, u);
+    }
+    if (!vis[u]) {
+        if (f == -1 || vis[f]) {
+            flag = true;
+        } else {
+            vis[f] = vis[u] = true;
+        }
+    }
+}
+
+int main() {
+    cin >> n;
+    for (int i = 1; i < n; i++) {
+        cin >> u >> v;
+        g[u].push_back(v);
+        g[v].push_back(u);
+    }
+    dfs(1, -1);
+    cout << (flag ? "First" : "Second") << endl;
+    return 0;
+}