挑战程序竞赛系列（60）：4.6树上的分治法（3）

挑战程序竞赛系列（60）：4.6树上的分治法（3）

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.StringTokenizer;

public class Main{

String INPUT = "./data/judge/201709/P2114.txt";

public static void main(String[] args) throws IOException {
new Main().run();
}

static final int MAX_N = 11111 + 16;
static final int INF   = 0x3f3f3f3f;

class Edge{
int to;
int cost;
Edge(int to, int cost){
this.to = to;
this.cost = cost;
}
}

List<Edge>[] g =  new ArrayList[MAX_N];
int N, K, tot, minv, cenv, point, ans;
int[] son  = new int[MAX_N];
int[] dis;
boolean[] vis = new boolean[MAX_N];

void init() {
tot = cenv = point = 0;
minv = INF;
for (int i = 0; i < N + 16; ++i) g[i] = new ArrayList<Edge>();
Arrays.fill(vis, false);
}

void add(int from, int to, int cost) {
g[from].add(new Edge(to, cost));
}

void dfs(int u, int fa) {
son[u] = 0;
int maxv = 0;
for (Edge e : g[u]) {
int v = e.to;
if (v == fa || vis[v]) continue;
dfs(v, u);
son[u] += son[v] + 1;
maxv = Math.max(maxv, son[v] + 1);
}
maxv = Math.max(maxv, point - 1 - son[u]);
if (maxv < minv) {
minv = maxv;
cenv = u;
}
}

void getDis(int u, int fa, int d) {
dis[tot++] = d;
for (Edge e : g[u]) {
int v = e.to;
int w = e.cost;
if (v == fa || vis[v]) continue;
getDis(v, u, d + w);
}
}

int count(int u, int d) {
tot = 0;
getDis(u, -1, d);
Arrays.sort(dis, 0, tot);
int l = 0, r = tot - 1, res = 0;
while (l < r) {
if (dis[l] + dis[r] <= K) {
res += r - l;
l++;
}
else r--;
}
l = 0;
r = tot - 1;
while (l < r) {
if (dis[l] + dis[r] < K) {
res -= r - l;
l++;
}
else r--;
}
return res;
}

void solve(int u) {
minv = INF;
point = point != 0 ? son[u] + 1 : N;
dfs(u, -1);
int root = cenv;
vis[root] = true;
ans += count(root, 0);
for (Edge e : g[root]) {
int v = e.to;
if (vis[v]) continue;
ans -= count(v, e.cost);
solve(v);
}
}

void read() {
while (true) {
N = ni();
if (N == 0) break;
init();
int cnt = 0;
for (int i = 1; i <= N; ++i) {
while (true) {
int to   = ni();
if (to == 0) break;
int cost = ni();
add(i - 1, to - 1, cost);
add(to - 1, i - 1, cost);
cnt += 2;
}
}

dis = new int[cnt + 16];

while (true) {
K = ni();
if (K == 0) break;
vis = new boolean[MAX_N];
ans = cenv = point = 0;
solve(0);
out.println(ans > 0 ? "AYE" :"NAY");
}

out.println(".");
}
}

FastScanner in;
PrintWriter out;

void run() throws IOException {
boolean oj;
try {
oj = ! System.getProperty("user.dir").equals("F:\\java_workspace\\leetcode");
} catch (Exception e) {
oj = System.getProperty("ONLINE_JUDGE") != null;
}

InputStream is = oj ? System.in : new FileInputStream(new File(INPUT));
in = new FastScanner(is);
out = new PrintWriter(System.out);
long s = System.currentTimeMillis();
read();
out.flush();
if (!oj){
System.out.println("[" + (System.currentTimeMillis() - s) + "ms]");
}
}

public boolean more(){
return in.hasNext();
}

public int ni(){
return in.nextInt();
}

public long nl(){
return in.nextLong();
}

public double nd(){
return in.nextDouble();
}

public String ns(){
return in.nextString();
}

public char nc(){
return in.nextChar();
}

class FastScanner {
BufferedReader br;
StringTokenizer st;
boolean hasNext;

public FastScanner(InputStream is) throws IOException {
br = new BufferedReader(new InputStreamReader(is));
hasNext = true;
}

public String nextToken() {
while (st == null || !st.hasMoreTokens()) {
try {
st = new StringTokenizer(br.readLine());
} catch (Exception e) {
hasNext = false;
return "##";
}
}
return st.nextToken();
}

String next = null;
public boolean hasNext(){
next = nextToken();
return hasNext;
}

public int nextInt() {
if (next == null){
hasNext();
}
String more = next;
next = null;
return Integer.parseInt(more);
}

public long nextLong() {
if (next == null){
hasNext();
}
String more = next;
next = null;
return Long.parseLong(more);
}

public double nextDouble() {
if (next == null){
hasNext();
}
String more = next;
next = null;
return Double.parseDouble(more);
}

public String nextString(){
if (next == null){
hasNext();
}
String more = next;
next = null;
return more;
}

public char nextChar(){
if (next == null){
hasNext();
}
String more = next;
next = null;
return more.charAt(0);
}
}

static class ArrayUtils {

public static void fill(int[][] f, int value) {
for (int i = 0; i < f.length; ++i) {
Arrays.fill(f[i], value);
}
}

public static void fill(int[][][] f, int value) {
for (int i = 0; i < f.length; ++i) {
fill(f[i], value);
}
}

public static void fill(int[][][][] f, int value) {
for (int i = 0; i < f.length; ++i) {
fill(f[i], value);
}
}
}
}