[AGC014D] Black and White Tree

R42961130

problem/AT2376/AT2376.cpp

@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> g[100005];
+int n, x, y, s[100005];
+bool flag;
+
+void dfs(int u, int p) {
+    s[u] = 1;
+    int t = 0;
+    for (int i = 0; i < g[u].size(); i++) {
+        if (g[u][i] != p) {
+            dfs(g[u][i], u);
+            t += s[g[u][i]];
+            s[u] ^= s[g[u][i]];
+        }
+    }
+    if (t > 1) flag = true;
+}
+
+int main() {
+    cin >> n;
+    for (int i = 1; i < n; i++) {
+        cin >> x >> y;
+        g[x].push_back(y);
+        g[y].push_back(x);
+    }
+    if (n & 1) {
+        cout << "First" << endl;
+        return 0;
+    }
+    dfs(1, 0);
+    if (flag) {
+        cout << "First" << endl;
+    }
+    else {
+        cout << "Second" << endl;
+    }
+    return 0;
+}