結果

問題 No.1094 木登り / Climbing tree
ユーザー OlandOland
提出日時 2020-06-26 21:01:28
言語 Java21
(openjdk 21)
結果
AC  
実行時間 1,056 ms / 2,000 ms
コード長 10,317 bytes
コンパイル時間 2,914 ms
コンパイル使用メモリ 83,812 KB
実行使用メモリ 161,676 KB
最終ジャッジ日時 2024-04-25 18:34:44
合計ジャッジ時間 28,718 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 52 ms
50,768 KB
testcase_01 AC 1,048 ms
156,564 KB
testcase_02 AC 617 ms
159,716 KB
testcase_03 AC 298 ms
59,136 KB
testcase_04 AC 557 ms
91,200 KB
testcase_05 AC 794 ms
123,876 KB
testcase_06 AC 662 ms
80,832 KB
testcase_07 AC 966 ms
156,748 KB
testcase_08 AC 928 ms
133,968 KB
testcase_09 AC 965 ms
133,840 KB
testcase_10 AC 968 ms
133,872 KB
testcase_11 AC 964 ms
133,876 KB
testcase_12 AC 956 ms
133,760 KB
testcase_13 AC 943 ms
133,928 KB
testcase_14 AC 1,056 ms
133,868 KB
testcase_15 AC 568 ms
77,276 KB
testcase_16 AC 888 ms
140,376 KB
testcase_17 AC 678 ms
104,920 KB
testcase_18 AC 719 ms
97,092 KB
testcase_19 AC 755 ms
105,964 KB
testcase_20 AC 992 ms
134,008 KB
testcase_21 AC 744 ms
106,868 KB
testcase_22 AC 994 ms
158,424 KB
testcase_23 AC 1,051 ms
161,676 KB
testcase_24 AC 955 ms
134,012 KB
testcase_25 AC 1,024 ms
158,148 KB
testcase_26 AC 903 ms
133,868 KB
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ソースコード

diff # 

import java.io.*;
import java.math.BigDecimal;
import java.util.*;

@SuppressWarnings("unused")
public class Main {
    FastScanner in;
    PrintWriter out;
    final static int MOD = (int)1e9+7;
    
    void solve(){
        int N = in.nextInt();
        ArrayList<ArrayList<Edge>> G = new ArrayList<>();
        for(int i = 0; i < N; i++) G.add(new ArrayList<>());
        for(int i = 0; i < N - 1; i++){
            int from = in.nextInt()-1;
            int to = in.nextInt()-1;
            int cost = in.nextInt();
            G.get(from).add(new Edge(from, to, cost));
            G.get(to).add(new Edge(to, from, cost));
        }
        
        LowestCommonAncestor lca = new LowestCommonAncestor(G, 0);
        
        int Q = in.nextInt();
        for(int i = 0; i < Q; i++){
            int s = in.nextInt()-1, t = in.nextInt()-1;
            out.println(lca.dist(s, t));
        }
    }
    
    class Edge implements Comparable<Edge>{
        int from;
        int to;
        int cost;
        public Edge(int f, int t, int c){
            from = f; to = t; cost = c;
        }
        @Override
        public int compareTo(Edge o) {
            return Integer.compare(this.cost, o.cost);
        }
    }
    
    class LowestCommonAncestor {
        int[] vs, depth, id, d;
        ArrayList<ArrayList<Edge>> T;
        SparseTableIndex sti;
        
        //Euler-Tour Technique
        public LowestCommonAncestor(ArrayList<ArrayList<Edge>> T, int root){
            vs = new int[T.size()*2-1];
            depth = new int[T.size()*2-1];
            id = new int[T.size()];
            d = new int[T.size()];
            this.T = T;
            dfsStack(root);
            sti = new SparseTableIndex(depth);
        }
        
        void dfsStack(int root){
            ArrayDeque<int[]> stack = new ArrayDeque<>();
            int k = 0;
            stack.addLast(new int[]{0, root, -1, 0, 0});
            while(!stack.isEmpty()){
                int[] node = stack.removeLast();
                int v = node[1], p = node[2], nd = node[3], cost = node[4];
                if(node[0] == 0){
                    id[v] = k;
                    vs[k] = v;
                    depth[k] = nd;
                    d[v] = cost;
                    k++;
                    for(Edge e : T.get(v)) {
                        int to = e.to;
                        if (to == p) continue;
                        stack.addLast(new int[]{1, v, p, nd, -1});
                        stack.addLast(new int[]{0, to, v, nd+1, d[v] + e.cost});
                    }
                }else{
                    vs[k] = v;
                    depth[k] = nd;
                    k++;
                }
            }
        }
        
        public int lca(int u, int v){
            int L = Math.min(id[u], id[v]), R = Math.max(id[u], id[v]);
            return vs[sti.get(L, R+1)];
        }
        
        public int dist(int u, int v){
            return d[u] + d[v] - 2 * d[lca(u, v)];
        }
        
        class SparseTableIndex {
            int[][] table;
            int[] height;
            int[] v;
            
            public SparseTableIndex(int[] v){
                init(v);
            }
            
            void init(int[] v){
                this.v = Arrays.copyOf(v, v.length);
                int n = v.length, h = 0;
                while((1<<h) <= n) h++;
                table = new int[h][1<<h];
                height = new int[n+1];
                for(int i = 2; i <= n; i++) height[i] = height[i>>1]+1;
                for(int i = 0; i < n; i++) table[0][i] = i;
                for(int i = 1; i < h; i++) {
                    for (int j = 0; j < n; j++) {
                        int x = table[i - 1][j], y = table[i - 1][Math.min(j + (1 << (i - 1)), n - 1)];
                        table[i][j] = v[x] <= v[y] ? x : y;
                    }
                }
            }
            
            public int get(int a, int b){
                int l = height[b-a];
                int x = table[l][a], y = table[l][b-(1<<l)];
                return v[x] <= v[y] ? x : y;
            }
        }
    }
    
    public static void main(String[] args) {
        new Main().m();
    }
    
    private void m() {
        in = new FastScanner(System.in);
        out = new PrintWriter(System.out);
        /*
        try {
            String path = "input.txt";
            out = new PrintWriter(new BufferedWriter(new FileWriter(new File(path))));
        }catch (IOException e){
            e.printStackTrace();
        }
        */
        solve();
        out.flush();
        in.close();
        out.close();
    }
    
    static class FastScanner {
        private Reader input;
        
        public FastScanner() {this(System.in);}
        public FastScanner(InputStream stream) {this.input = new BufferedReader(new InputStreamReader(stream));}
        public void close() {
            try {
                this.input.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        
        public long nextLong() {
            try {
                int sign = 1;
                int b = input.read();
                while ((b < '0' || '9' < b) && b != '-' && b != '+') {
                    b = input.read();
                }
                if (b == '-') {
                    sign = -1;
                    b = input.read();
                } else if (b == '+') {
                    b = input.read();
                }
                long ret = b - '0';
                while (true) {
                    b = input.read();
                    if (b < '0' || '9' < b) return ret * sign;
                    ret *= 10;
                    ret += b - '0';
                }
            } catch (IOException e) {
                e.printStackTrace();
                return -1;
            }
        }
        
        public double nextDouble() {
            try {
                double sign = 1;
                int b = input.read();
                while ((b < '0' || '9' < b) && b != '-' && b != '+') {
                    b = input.read();
                }
                if (b == '-') {
                    sign = -1;
                    b = input.read();
                } else if (b == '+') {
                    b = input.read();
                }
                double ret = b - '0';
                while (true) {
                    b = input.read();
                    if (b < '0' || '9' < b) break;
                    ret *= 10;
                    ret += b - '0';
                }
                if (b != '.') return sign * ret;
                double div = 1;
                b = input.read();
                while ('0' <= b && b <= '9') {
                    ret *= 10;
                    ret += b - '0';
                    div *= 10;
                    b = input.read();
                }
                return sign * ret / div;
            } catch (IOException e) {
                e.printStackTrace();
                return Double.NaN;
            }
        }
        
        public char nextChar() {
            try {
                int b = input.read();
                while (Character.isWhitespace(b)) {
                    b = input.read();
                }
                return (char) b;
            } catch (IOException e) {
                e.printStackTrace();
                return 0;
            }
        }
        
        public String nextStr() {
            try {
                StringBuilder sb = new StringBuilder();
                int b = input.read();
                while (Character.isWhitespace(b)) {
                    b = input.read();
                }
                while (b != -1 && !Character.isWhitespace(b)) {
                    sb.append((char) b);
                    b = input.read();
                }
                return sb.toString();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }
        
        public String nextLine() {
            try {
                StringBuilder sb = new StringBuilder();
                int b = input.read();
                while (b != -1 && b != '\n') {
                    sb.append((char) b);
                    b = input.read();
                }
                return sb.toString();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }
        
        public int[] nextIntArray(int n) {
            int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        
        public int[] nextIntArrayDec(int n) {
            int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt() - 1;
            }
            return res;
        }
        
        public int[] nextIntArray1Index(int n) {
            int[] res = new int[n + 1];
            for (int i = 0; i < n; i++) {
                res[i + 1] = nextInt();
            }
            return res;
        }
        
        public long[] nextLongArray(int n) {
            long[] res = new long[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextLong();
            }
            return res;
        }
        
        public long[] nextLongArrayDec(int n) {
            long[] res = new long[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextLong() - 1;
            }
            return res;
        }
        
        public long[] nextLongArray1Index(int n) {
            long[] res = new long[n + 1];
            for (int i = 0; i < n; i++) {
                res[i + 1] = nextLong();
            }
            return res;
        }
        
        public double[] nextDoubleArray(int n) {
            double[] res = new double[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextDouble();
            }
            return res;
        }
    }
}
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