diff --git a/TangDou/Topic/HuanGenDp/CF1406C.cpp b/TangDou/Topic/HuanGenDp/CF1406C.cpp
index cf62646..7088ddf 100644
--- a/TangDou/Topic/HuanGenDp/CF1406C.cpp
+++ b/TangDou/Topic/HuanGenDp/CF1406C.cpp
@@ -21,23 +21,15 @@ void dfs(int u, int fa) {
     for (int i = h[u]; ~i; i = ne[i]) { // 枚举u的每一条出边
         int v = e[i];
         if (v == fa) continue;
-        dfs(v, u);
-        sz[u] += sz[v];
+        dfs(v, u);      // 先把v为根的子树遍历完
+        sz[u] += sz[v]; // 把 v中获取填充的sz[v]值，用于组装自己sz[u]
         son[u] = max(son[u], sz[v]);
     }
     son[u] = max(son[u], n - sz[u]);
     if ((son[u] << 1) <= n) r2 = r1, r1 = u;
 }
-/*
-1 2
-1 2
-1 3
-2 3
-*/
+
 signed main() {
-#ifndef ONLINE_JUDGE
-    freopen("CF1406C.in", "r", stdin);
-#endif
     int T;
     cin >> T;
     while (T--) {