[洛谷P3258] [JLOI2014]松鼠的新家

题目链接：##

点我

题目分析：##

树链剖分
每一次按顺序走到下一个点可以看作沿途的点权+1，注意出发时的点不能+1

代码：##

// luogu-judger-enable-o2
#include<bits/stdc++.h>
#define N (600000 + 5)
using namespace std;
inline int read() {
    int cnt = 0, f = 1; char c;
    c = getchar();
    while (!isdigit(c)) {
        if (c == '-') f = -f;
        c = getchar();
    }
    while (isdigit(c)) {
        cnt = (cnt << 3) + (cnt << 1) + c - '0';
        c = getchar();
    }
    return cnt * f;
}
int son[N], siz[N], dep[N], father[N], top[N], num[N], id[N], idx;
int first[N], nxt[N], to[N], tot;
void Add(int x, int y) {
    nxt[++tot] = first[x];
    first[x] = tot;
    to[tot] = y;
}

void dfs1(int cur, int fa) {
    father[cur] = fa, siz[cur] = 1, dep[cur] = dep[fa] + 1;
    for (register int i = first[cur]; i; i = nxt[i]) {
        int v = to[i];	
        if (v != fa) {
            dfs1(v, cur);
            siz[cur] += siz[v];
            if (siz[son[cur]] < siz[v]) son[cur] = v;
        }
    }
}

void dfs2(int cur, int tp) {
    top[cur] = tp; num[cur] = ++idx; id[idx] = cur;
    if (son[cur]) dfs2(son[cur], tp);
    for (register int i = first[cur]; i; i = nxt[i]) {
        int v = to[i];
        if (!num[v]) dfs2(v, v);
    }
}

struct node {
    int l; int r;
    int sum, tag;
    #define l(p) tree[p].l
    #define r(p) tree[p].r
    #define sum(p) tree[p].sum
    #define tag(p) tree[p].tag
}tree[N * 4];

void push_up(int p) {
    sum(p) = sum(p << 1) + sum(p << 1 | 1);
}

void push_down(int p) {
    sum(p << 1) += (r(p << 1) - l(p << 1) + 1) * tag(p);
    sum(p << 1 | 1) += (r(p << 1 | 1) - l(p << 1 | 1) + 1) * tag(p);
    tag(p << 1) += tag(p); tag(p << 1 | 1) += tag(p);
    tag(p) = 0; 
}

void build_tree(int p, int l, int r) {
    l(p) = l; r(p) = r;
    if (l == r) {
        sum(p) = 0; return;
    }
    int mid = (l + r) >> 1;
    build_tree(p << 1, l, mid);
    build_tree(p << 1 | 1, mid + 1, r);
    push_up(p);
}

void modify (int p, int l, int r, int d) {
    if (l <= l(p) && r >= r(p)) {
        tag(p) += d;
        sum(p) += (r(p) - l(p) + 1) * d;
        return;
    }
    push_down(p);
    int mid = (l(p) + r(p)) >> 1;
    if (l <= mid) modify(p << 1, l, r, d);
    if (r > mid) modify(p << 1 | 1, l, r, d);
    push_up(p);
}

int query (int p, int l, int r) {
    if (l <= l(p) && r >= r(p)) return sum(p);
    push_down(p);
    int val = 0;
    int mid = (l(p) + r(p)) >> 1;
    if (l <= mid) val += query(p << 1, l, r);
    if (r > mid) val += query(p << 1 | 1, l, r);
    return val;
}

void chain_modify(int u, int v, int d) {
    while (top[u] != top[v]) {
        if (dep[top[u]] < dep[top[v]]) swap(u, v);
        modify(1, num[top[u]], num[u], d);
        u = father[top[u]];
    }
    if (dep[u] < dep[v]) swap(u, v);
    modify(1, num[v], num[u], d);
}

int n, A[N], x, y;
int main() {
    n = read(); 
    for (register int i = 1; i <= n; i++) A[i] = read();
    for (register int i = 1; i < n; i++) {
        x = read(); y = read();
        Add(x, y); Add(y, x);
    }
    dfs1(1, 0); dfs2(1, 1);build_tree(1, 1, n);
    for (register int i = 1; i < n; i++) chain_modify(A[i], A[i + 1] , 1);
    for (register int i = 1; i <= n; i++) {
        if (i != A[1]) 
        printf("%d
", query(1, num[i], num[i]) - 1);
        else printf("%d
", query(1, num[i], num[i]));
    }
    return 0;
}