|
|
package class16;
|
|
|
|
|
|
import java.util.ArrayList;
|
|
|
import java.util.Comparator;
|
|
|
import java.util.HashMap;
|
|
|
|
|
|
// OJ链接：https://www.lintcode.com/problem/topological-sorting
|
|
|
public class Code03_TopologicalOrderDFS2 {
|
|
|
|
|
|
// 不要提交这个类
|
|
|
public static class DirectedGraphNode {
|
|
|
public int label;
|
|
|
public ArrayList<DirectedGraphNode> neighbors;
|
|
|
|
|
|
public DirectedGraphNode(int x) {
|
|
|
label = x;
|
|
|
neighbors = new ArrayList<DirectedGraphNode>();
|
|
|
}
|
|
|
}
|
|
|
|
|
|
// 提交下面的
|
|
|
public static class Record {
|
|
|
public DirectedGraphNode node;
|
|
|
public long nodes;
|
|
|
|
|
|
public Record(DirectedGraphNode n, long o) {
|
|
|
node = n;
|
|
|
nodes = o;
|
|
|
}
|
|
|
}
|
|
|
|
|
|
public static class MyComparator implements Comparator<Record> {
|
|
|
|
|
|
@Override
|
|
|
public int compare(Record o1, Record o2) {
|
|
|
return o1.nodes == o2.nodes ? 0 : (o1.nodes > o2.nodes ? -1 : 1);
|
|
|
}
|
|
|
}
|
|
|
|
|
|
public static ArrayList<DirectedGraphNode> topSort(ArrayList<DirectedGraphNode> graph) {
|
|
|
HashMap<DirectedGraphNode, Record> order = new HashMap<>();
|
|
|
for (DirectedGraphNode cur : graph) {
|
|
|
f(cur, order);
|
|
|
}
|
|
|
ArrayList<Record> recordArr = new ArrayList<>();
|
|
|
for (Record r : order.values()) {
|
|
|
recordArr.add(r);
|
|
|
}
|
|
|
recordArr.sort(new MyComparator());
|
|
|
ArrayList<DirectedGraphNode> ans = new ArrayList<DirectedGraphNode>();
|
|
|
for (Record r : recordArr) {
|
|
|
ans.add(r.node);
|
|
|
}
|
|
|
return ans;
|
|
|
}
|
|
|
|
|
|
// 当前来到cur点，请返回cur点所到之处，所有的点次！
|
|
|
// 返回（cur，点次）
|
|
|
// 缓存！！！！！order
|
|
|
// key : 某一个点的点次，之前算过了！
|
|
|
// value : 点次是多少
|
|
|
public static Record f(DirectedGraphNode cur, HashMap<DirectedGraphNode, Record> order) {
|
|
|
if (order.containsKey(cur)) {
|
|
|
return order.get(cur);
|
|
|
}
|
|
|
// cur的点次之前没算过！
|
|
|
long nodes = 0;
|
|
|
for (DirectedGraphNode next : cur.neighbors) {
|
|
|
nodes += f(next, order).nodes;
|
|
|
}
|
|
|
Record ans = new Record(cur, nodes + 1);
|
|
|
order.put(cur, ans);
|
|
|
return ans;
|
|
|
}
|
|
|
|
|
|
}
|
