結果

問題 No.872 All Tree Path
ユーザー kitakitalily
提出日時 2019-08-31 00:39:19
言語 Java
(openjdk 23)
結果
AC  
実行時間 540 ms / 3,000 ms
コード長 2,882 bytes
コンパイル時間 5,364 ms
コンパイル使用メモリ 78,260 KB
実行使用メモリ 120,448 KB
最終ジャッジ日時 2024-11-22 06:36:47
合計ジャッジ時間 8,460 ms
ジャッジサーバーID
(参考情報)
judge2 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 18
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ソースコード

diff #
プレゼンテーションモードにする

import java.util.*;
import java.io.*;
public class Main {
static int n;
static ArrayList<Edge>[] edges;
static int[] cnt;
static long ret = 0;
public static void main(String[] args){
FastScanner scanner = new FastScanner();
n = scanner.nextInt();
int[] u = new int[n];
int[] v = new int[n];
int[] w = new int[n];
edges = new ArrayList[n];
cnt = new int[n];
for(int i = 0; i < n; i++){
edges[i] = new ArrayList<Edge>();
}
for(int i = 0; i < n-1; i++){
u[i] = scanner.nextInt()-1;
v[i] = scanner.nextInt()-1;
w[i] = scanner.nextInt();
edges[u[i]].add(new Edge(v[i],w[i]));
edges[v[i]].add(new Edge(u[i],w[i]));
}
dfs(0,-1);
System.out.println(ret*2L);
}
public static long dfs(int i, int parent){
cnt[i] = 1;
int r = 0;
for(Edge e : edges[i]){
if(e.to == parent){
r = e.cost;
}else{
cnt[i] += dfs(e.to,i);
}
}
ret += 1L*r*cnt[i]*(n-cnt[i]);
return cnt[i];
}
public static class Edge{
int to;
int cost;
Edge(int to, int cost){
this.to = to;
this.cost = cost;
}
}
private static class FastScanner {
private final InputStream in = System.in;
private final byte[] buffer = new byte[1024];
private int ptr = 0;
private int buflen = 0;
private boolean hasNextByte() {
if (ptr < buflen) {
return true;
}else{
ptr = 0;
try {
buflen = in.read(buffer);
} catch (IOException e) {
e.printStackTrace();
}
if (buflen <= 0) {
return false;
}
}
return true;
}
private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
public String next() {
if (!hasNext()) throw new NoSuchElementException();
StringBuilder sb = new StringBuilder();
int b = readByte();
while(isPrintableChar(b)) {
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
public long nextLong() {
if (!hasNext()) throw new NoSuchElementException();
long n = 0;
boolean minus = false;
int b = readByte();
if (b == '-') {
minus = true;
b = readByte();
}
if (b < '0' || '9' < b) {
throw new NumberFormatException();
}
while(true){
if ('0' <= b && b <= '9') {
n *= 10;
n += b - '0';
}else if(b == -1 || !isPrintableChar(b)){
return minus ? -n : n;
}else{
throw new NumberFormatException();
}
b = readByte();
}
}
public int nextInt() {
long nl = nextLong();
if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
return (int) nl;
}
public double nextDouble() { return Double.parseDouble(next());}
}
}
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