'commit'

TangDou/Topic/HuanGenDp/CF1406.cpp

@@ -1,15 +1,17 @@
 #include <bits/stdc++.h>
 using namespace std;
-const int maxn = 1e5 + 100;
-typedef long long LL;
-vector<LL> g[maxn];
-LL siz[maxn], son[maxn];
-LL r1, r2, n;
-void dfs(LL u, LL fa) {
+const int N = 1e5 + 10;
+#define int long long
+#define endl "\n"
+
+vector<int> g[N];
+int siz[N], son[N];
+int r1, r2, n;
+void dfs(int u, int fa) {
     siz[u] = 1;
     son[u] = 0;
-    for (LL i = 0; i < g[u].size(); i++) {
-        LL v = g[u][i];
+    for (int i = 0; i < g[u].size(); i++) {
+        int v = g[u][i];
         if (v == fa) continue;
         dfs(v, u);
         siz[u] += siz[v];
@@ -18,14 +20,14 @@ void dfs(LL u, LL fa) {
     son[u] = max(son[u], n - siz[u]);
     if ((son[u] << 1) <= n) r2 = r1, r1 = u;
 }
-int main() {
-    LL t;
+signed main() {
+    int t;
     cin >> t;
     while (t--) {
         cin >> n;
-        for (LL i = 0; i <= n + 10; i++) g[i].clear(), siz[i] = 0, son[i] = 0;
-        for (LL i = 1; i < n; i++) {
-            LL x, y;
+        for (int i = 0; i <= n + 10; i++) g[i].clear(), siz[i] = 0, son[i] = 0;
+        for (int i = 1; i < n; i++) {
+            int x, y;
             cin >> x >> y;
             g[x].push_back(y);
             g[y].push_back(x);
@@ -33,12 +35,12 @@ int main() {
         r1 = r2 = 0;
         dfs(1, 0);
         if (!r2) {
-            LL r3 = g[r1][0];
+            int r3 = g[r1][0];
             cout << r1 << " " << r3 << endl;
             cout << r1 << " " << r3 << endl;
         } else {
-            LL r3 = r1;
-            for (LL i = 0; i < g[r2].size(); i++) {
+            int r3 = r1;
+            for (int i = 0; i < g[r2].size(); i++) {
                 r3 = g[r2][i];
                 if (r3 != r1) break;
             }