kk

src/main/java/com/dota/graph/Solution.java

@@ -5,6 +5,7 @@ import java.util.*;
 class Solution {
 
     long res = 0;
+    int sum = 0;
 
     public long minimumFuelCost(int[][] roads, int seats) {
         List<Integer>[] map = new List[roads.length + 1];
@@ -27,10 +28,43 @@ class Solution {
             if (i != from) {
                 int childSum = dfs(i, start, seats, map);
                 cur += childSum;
-                res += (childSum + seats - 1)/seats;
+                res += (childSum + seats - 1) / seats;
             }
         }
 
         return cur;
     }
-}
+
+    // 1466. 重新规划路线
+    public int minReorder(int n, int[][] connections) {
+        List<Integer>[] list = new List[n];
+        List<Integer>[] otherList = new List[n];
+        for (int i = 0; i < list.length; i++) {
+            list[i] = new ArrayList<>();
+            otherList[i] = new ArrayList<>();
+        }
+
+        for (int[] ints : connections) {
+            list[ints[0]].add(ints[1]);
+            otherList[ints[1]].add(ints[0]);
+        }
+
+        dfs(0, -1, list, otherList);
+        return sum;
+    }
+
+    private void dfs(int now, int parent, List<Integer>[] list, List<Integer>[] otherList) {
+        for (int i = 0; i < list[now].size(); i++) {
+            if (list[now].get(i) != parent) {
+                sum++;
+                dfs(list[now].get(i), now, list, otherList);
+            }
+        }
+
+        for (int i = 0; i < otherList[now].size(); i++) {
+            if (otherList[now].get(i) != parent) {
+                dfs(otherList[now].get(i), now, list, otherList);
+            }
+        }
+    }
+}