結果
| 問題 |
No.806 木を道に
|
| コンテスト | |
| ユーザー |
 mnzn
|
| 提出日時 | 2020-04-11 05:12:05 |
| 言語 | C#(csc) (csc 3.9.0) |
| 結果 |
WA
|
| 実行時間 | - |
| コード長 | 9,841 bytes |
| コンパイル時間 | 984 ms |
| コンパイル使用メモリ | 110,848 KB |
| 実行使用メモリ | 52,016 KB |
| 最終ジャッジ日時 | 2024-09-17 08:22:23 |
| 合計ジャッジ時間 | 7,084 ms |
|
ジャッジサーバーID （参考情報） |
judge2 / judge1 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 2 |
| other | AC * 9 WA * 18 |
コンパイルメッセージ
Microsoft (R) Visual C# Compiler version 3.9.0-6.21124.20 (db94f4cc) Copyright (C) Microsoft Corporation. All rights reserved.
ソースコード
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Program
{
static void Main(string[] args)
{
var N = sc.ReadInt();
var G = new List<int>[N];
var dij = new Dijkstra(N);
for (int i = 0; i < N; i++)
{
G[i] = new List<int>();
}
for (int i = 0; i < N - 1; i++)
{
var x = sc.ReadInt() - 1;
var y = sc.ReadInt() - 1;
dij.Add(x, y, -1);
dij.Add(y, x, -1);
}
var dist = dij.Calc(0);
var p1 = Array.IndexOf(dist, dist.Min());
dist = dij.Calc(p1);
var diameter = -dist.Min();
var ans = N - diameter - 1;
Console.WriteLine(ans);
}
class Dijkstra
{
public int V { get; set; }
public int E { get; set; }
public List<Edge>[] G { get; set; }
public Dijkstra(int n)
{
this.V = n;
this.G = new List<Edge>[V];
for (int i = 0; i < V; i++)
{
this.G[i] = new List<Edge>();
}
}
public void Add(int a, int b, long cost = 1)
{
this.G[a].Add(new Edge(b, cost));
this.G[b].Add(new Edge(a, cost));
this.E++;
}
public long GetMinCost(int start, int goal)
{
var cost = new long[V];
for (int i = 0; i < V; i++) cost[i] = long.MaxValue;
cost[start] = 0;
var capacity = Math.Max(1, E);
var q = new PriorityQueue<P>(capacity, false);
q.Enqueue(new P(start, 0));
while (q.Count > 0)
{
var p = q.Dequeue();
if (p.Cost != cost[p.A]) continue;
foreach (var e in this.G[p.A])
{
if (cost[e.To] > p.Cost + e.Cost)
{
cost[e.To] = p.Cost + e.Cost;
q.Enqueue(new P(e.To, cost[e.To]));
}
}
}
return cost[goal] == long.MaxValue ? -1 : cost[goal];
}
public long[] Calc(int start)
{
var visited = new bool[V];
var cost = new long[V];
for (int i = 0; i < V; i++) cost[i] = long.MaxValue;
cost[start] = 0;
var capacity = Math.Max(1, E);
var q = new PriorityQueue<P>(capacity, false);
q.Enqueue(new P(start, 0));
while (q.Count > 0)
{
var p = q.Dequeue();
visited[p.A] = true;
if (p.Cost != cost[p.A]) continue;
foreach (var e in this.G[p.A])
{
if (cost[e.To] > p.Cost + e.Cost && !visited[e.To])
{
cost[e.To] = p.Cost + e.Cost;
q.Enqueue(new P(e.To, cost[e.To]));
}
}
}
return cost;
}
public struct Edge
{
public int To;
public long Cost;
public Edge(int to, long cost)
{
this.To = to;
this.Cost = cost;
}
}
public struct P : IComparable<P>
{
public int A;
public long Cost;
public P(int a, long cost)
{
this.A = a;
this.Cost = cost;
}
public int CompareTo(P other)
{
return this.Cost.CompareTo(other.Cost);
}
}
}
class PriorityQueue<T>
{
public readonly T[] Array;
public readonly bool Greater;
public int Count { get; private set; } = 0;
private IComparer<T> Cmp;
public PriorityQueue(int capacity, bool greater = true, IComparer<T> cmp = null)
{
this.Cmp = cmp;
if (cmp == null)
{
this.Cmp = Comparer<T>.Default;
}
this.Array = new T[capacity];
this.Greater = greater;
}
public void Enqueue(T item)
{
this.Array[this.Count] = item;
this.Count += 1;
this.UpHeap();
}
public T Dequeue()
{
this.Swap(0, this.Count - 1);
this.Count -= 1;
this.DownHeap();
return this.Array[this.Count];
}
public T Peek()
{
return this.Array[0];
}
private void UpHeap()
{
var n = this.Count - 1;
while (n != 0)
{
var parent = (n - 1) / 2;
if (this.Compare(this.Array[n], this.Array[parent]) > 0)
{
this.Swap(n, parent);
n = parent;
}
else
{
break;
}
}
}
private void DownHeap()
{
var parent = 0;
while (true)
{
var child = 2 * parent + 1;
if (child > this.Count - 1) break;
if (child < this.Count - 1 && this.Compare(this.Array[child], this.Array[child + 1]) < 0)
{
child += 1;
}
if (this.Compare(this.Array[parent], this.Array[child]) < 0)
{
this.Swap(parent, child);
parent = child;
}
else
{
break;
}
}
}
private int Compare(T a, T b)
{
var c = this.Cmp.Compare(a, b);
if (!this.Greater)
{
c = -c;
}
return c;
}
private void Swap(int a, int b)
{
var tmp = this.Array[a];
this.Array[a] = this.Array[b];
this.Array[b] = tmp;
}
}
static Scanner sc = new Scanner();
}
class Scanner
{
string[] S = new string[0];
int Index = 0;
char[] Separators = new char[] { ' ' };
public string Next()
{
if (this.Index < this.S.Length) return this.S[this.Index++];
var line = "";
while (line == "") line = Console.ReadLine();
this.S = line.Split(this.Separators, StringSplitOptions.RemoveEmptyEntries);
if (this.S.Length == 0) return this.Next();
this.Index = 0;
return this.S[this.Index++];
}
public string ReadStr()
{
return this.Next();
}
public char ReadChar()
{
return this.Next()[0];
}
public int ReadInt()
{
return int.Parse(this.Next());
}
public uint ReadUInt()
{
return uint.Parse(this.Next());
}
public long ReadLong()
{
return long.Parse(this.Next());
}
public double ReadDouble()
{
return double.Parse(this.Next());
}
public Tuple<int, int> ReadTup(int add = 0)
{
return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add);
}
public Tuple<long, long> ReadTupLong(int add = 0)
{
return Tuple.Create(this.ReadLong() + add, this.ReadLong() + add);
}
public Tuple<int, int, int> ReadTup3(int add = 0)
{
return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add);
}
public Tuple<int, int, int, int> ReadTup4(int add = 0)
{
return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add);
}
public int[] ReadIntArray(int n)
{
var array = new int[n];
for (int i = 0; i < array.Length; i++)
{
array[i] = this.ReadInt();
}
return array;
}
public long[] ReadLongArray(int n)
{
var array = new long[n];
for (int i = 0; i < array.Length; i++)
{
array[i] = this.ReadLong();
}
return array;
}
public double[] ReadDoubleArray(int n)
{
var array = new double[n];
for (int i = 0; i < array.Length; i++)
{
array[i] = this.ReadDouble();
}
return array;
}
public char[] ReadCharArray(int n)
{
var array = new char[n];
for (int i = 0; i < array.Length; i++)
{
array[i] = this.ReadChar();
}
return array;
}
public string[] ReadStrArray(int n)
{
var array = new string[n];
for (int i = 0; i < array.Length; i++)
{
array[i] = this.ReadStr();
}
return array;
}
public Tuple<long, long>[] ReadTupLongArray(int n, int add = 0)
{
var array = new Tuple<long, long>[n];
for (int i = 0; i < n; i++)
{
array[i] = this.ReadTupLong(add);
}
return array;
}
public Tuple<int, int>[] ReadTupArray(int n, int add = 0)
{
var array = new Tuple<int, int>[n];
for (int i = 0; i < n; i++)
{
array[i] = this.ReadTup(add);
}
return array;
}
public Tuple<int, int, int>[] ReadTup3Array(int n, int add = 0)
{
var array = new Tuple<int, int, int>[n];
for (int i = 0; i < n; i++)
{
array[i] = this.ReadTup3(add);
}
return array;
}
public Tuple<int, int, int, int>[] ReadTup4Array(int n, int add = 0)
{
var array = new Tuple<int, int, int, int>[n];
for (int i = 0; i < n; i++)
{
array[i] = this.ReadTup4(add);
}
return array;
}
}