c

ACWing/src/LCA/Tarjan求LCA.java

@@ -66,7 +66,7 @@ public class Tarjan求LCA {
         for (int i = 0; i < m; i++) {
             addq(nextInt(), nextInt(), i);
         }//存储询问
-        tarjan(root, 0);
+        tarjan(root, -1);
         for (int i = 0; i < m; i++) {
             bw.write(result[i] + "\n");
         }

ACWing/src/LCA/祖孙询问.java

@@ -102,11 +102,16 @@ public class 祖孙询问 {
         h[b] = cnt++;
     }
 
+    /**
+     * bfs求深度和lca
+     *
+     * @param root
+     */
     static void bfs(int root) {
         Arrays.fill(depth, inf);
         depth[0] = 0;
-        depth[root] = 1;
-        q.add(root);
+        depth[root] = 1;//规定根节点深度为1
+        q.add(root);//加入根节点
         while (!q.isEmpty()) {
             int t = q.poll();
             for (int i = h[t]; i != 0; i = ne[i]) {
@@ -115,7 +120,7 @@ public class 祖孙询问 {
                     depth[j] = depth[t] + 1;//bfs拓展
                     q.add(j);
                     up[j][0] = t;//记录第一个
-                    for (int k = 1; k <= 17; k++) {//记录后面的up
+                    for (int k = 1; k <= 17; k++) {//记录后面的up,虽然有无效计算,但胜在好写
                         up[j][k] = up[up[j][k - 1]][k - 1];
                     }
                 }

ACWing/src/graph/dijkstra.java

@@ -55,11 +55,11 @@ public class dijkstra {
             c = nextInt();
             add(a, b, c);
         }
-        Arrays.fill(dis, Integer.MAX_VALUE);
         dij(s);
     }
 
     private static void dij(int s) throws IOException {
+        Arrays.fill(dis, Integer.MAX_VALUE);
         q.add(new node(s, 0));
         dis[s] = 0;
         while (!q.isEmpty()) {

ACWing/src/graph/有向图的强联通分量/受欢迎的牛.java

@@ -3,7 +3,9 @@ package graph.有向图的强联通分量;
 import java.util.Scanner;
 
 /**
+ * tarjan求强联通分量
  * https://www.luogu.com.cn/blog/zyb2624936151/tarjan
+ *
  */
 @SuppressWarnings("all")
 public class 受欢迎的牛 {