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

@@ -0,0 +1,36 @@
+package com.dota.graph;
+
+import java.util.*;
+
+class Solution {
+
+    long res = 0;
+
+    public long minimumFuelCost(int[][] roads, int seats) {
+        List<Integer>[] map = new List[roads.length + 1];
+        for (int i = 0; i < map.length; i++) {
+            map[i] = new ArrayList<>();
+        }
+
+        for (int[] road : roads) {
+            map[road[0]].add(road[1]);
+            map[road[1]].add(road[0]);
+        }
+
+        dfs(0, -1, seats, map);
+        return res;
+    }
+
+    int dfs(int start, int from, int seats, List<Integer>[] map) {
+        int cur = 1;
+        for (Integer i : map[start]) {
+            if (i != from) {
+                int childSum = dfs(i, start, seats, map);
+                cur += childSum;
+                res += (childSum + seats - 1)/seats;
+            }
+        }
+
+        return cur;
+    }
+}