洛谷 P3806 【模板】点分治1

传送门

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using p = pair<int, int>;
const int maxn(1e4 + 10);
const int maxm(1e2 + 10);
const int maxk(2e7 + 10);
int ecnt, head[maxn];
int que[maxm], ans[maxn];
int rt, tot, root[maxn], siz[maxn], maxp[maxn];
int cnt, tmp[maxn], dis[maxn];
bool vis[maxn], judge[maxk];

struct edge {
    int to, wt, nxt;
} edges[maxn << 1];

template<typename T = int>
inline const T read()
{
    T x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' or ch > '9') {
        if (ch == '-') f = -1;
        ch = getchar();
    }
    while (ch >= '0' and ch <= '9') {
        x = (x << 3) + (x << 1) + ch - '0';
        ch = getchar();
    }
    return x * f;
}

template<typename T>
inline void write(T x, bool ln)
{
    if (x < 0) {
        putchar('-');
        x = -x;
    }
    if (x > 9) write(x / 10, false);
    putchar(x % 10 + '0');
    if (ln) putchar(10);
}

inline void addEdge(int u, int v, int w)
{
    edges[ecnt].to = v;
    edges[ecnt].wt = w;
    edges[ecnt].nxt = head[u];
    head[u] = ecnt++;
}

void getRoot(int u, int f)
{
    siz[u] = 1;
    maxp[u] = 0;
    for (int i = head[u]; compl i; i = edges[i].nxt) {
        int v = edges[i].to;
        if (vis[v] or v == f) {
            continue;
        }
        getRoot(v, u);
        siz[u] += siz[v];
        maxp[u] = max(maxp[u], siz[v]);
    }
    maxp[u] = max(maxp[u], tot - siz[u]);
    if (maxp[u] < maxp[rt]) {
        rt = u;
    }
}

void getDis(int u, int f)
{
    tmp[cnt++] = dis[u];
    for (int i = head[u]; compl i; i = edges[i].nxt) {
        int v = edges[i].to, w = edges[i].wt;
        if (vis[v] or v == f) {
            continue;
        }
        dis[v] = dis[u] + w;
        getDis(v, u);
    }
}

void solve(int u, int m)
{
    static queue<int> q;
    for (int i = head[u]; compl i; i = edges[i].nxt) {
        int v = edges[i].to, w = edges[i].wt;
        if (vis[v]) {
            continue;
        }
        cnt = 0;
        dis[v] = w;
        getDis(v, u);
        for (int j = 0; j < cnt; ++j) {
            for (int k = 0; k < m; ++k) {
                if (que[k] >= tmp[j]) {
                    ans[k] or_eq judge[que[k] - tmp[j]];
                }
            }
        }
        for (int j = 0; j < cnt; ++j) {
            q.push(tmp[j]);
            judge[tmp[j]] = true;
        }
    }
    while (not q.empty()) {
        judge[q.front()] = false;
        q.pop();
    }
}

void divide(int u, int m)
{
    vis[u] = judge[0] = true;
    solve(u, m);
    for (int i = head[u]; compl i; i = edges[i].nxt) {
        int v = edges[i].to;
        if (vis[v]) {
            continue;
        }
        maxp[rt = 0] = tot = siz[v];
        getRoot(v, 0);
        getRoot(rt, 0);
        divide(rt, m);
    }
}

int main()
{
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    memset(head, -1, sizeof head);
    int n = read(), m = read();
    for (int i = 0; i < n - 1; ++i) {
        int u = read(), v = read(), w = read();
        addEdge(u, v, w);
        addEdge(v, u, w);
    }
    for (int i = 0; i < m; ++i) {
        que[i] = read();
    }
    tot = maxp[0] = n;
    getRoot(1, 0);
    getRoot(rt, 0);
    divide(rt, m);
    for (int i = 0; i < m; ++i) {
        puts(ans[i] ? "AYE" : "NAY");
    }
    return 0;
}