Luogu P3178 树上操作（树链剖分+线段树）

Posted 2021-01-14 water-mi

题意

见原题

题解

重链剖分模板题

#include <cstdio>
#include <algorithm>
using std::swap;
typedef long long ll;

const int N = 1e5 + 10;
int n, m, c[N], opt, x, y;
int dep[N], siz[N], fa[N], son[N];
int top[N], dfn[N], w[N], time;
int cnt, from[N], to[N << 1], nxt[N << 1];
ll val[N << 2], add[N << 2];
inline void addEdge(int u, int v){
    to[++cnt] = v, nxt[cnt] = from[u], from[u] = cnt;
}

void dfs1(int u) {
    dep[u] = dep[fa[u]] + 1, siz[u] = 1;
    for (int i = from[u]; i; i = nxt[i]) {
        int v = to[i]; if(v == fa[u]) continue;
        fa[v] = u, dfs1(v), siz[u] += siz[v];
        if(siz[v] > siz[son[u]]) son[u] = v;
    }
}
void dfs2(int u, int t) {
    top[u] = t, dfn[u] = ++time, w[time] = c[u];
    if(!son[u]) return ; dfs2(son[u], t);
    for(int i = from[u]; i; i = nxt[i]) {
        int v = to[i];
        if(v != fa[u] && v != son[u])
            dfs2(v, v);
    }
}

inline void pushup(int o, int lc, int rc) {
    val[o] = val[lc] + val[rc];
}
inline void pushdown(int o, int lc, int rc, int len) {
    if(add[o]) {
        add[lc] += add[o], add[rc] += add[o];
        val[lc] += add[o] * (len - (len >> 1));
        val[rc] += add[o] * (len >> 1);
        add[o] = 0;
    }
}
void build(int o = 1, int l = 1, int r = n) {
    if(l == r) { val[o] = w[l]; return ; }
    int mid = (l + r) >> 1, lc = o << 1, rc = lc | 1;
    build(lc, l, mid), build(rc, mid + 1, r), pushup(o, lc, rc);
}
void upt(int ul, int ur, ll k, int o = 1, int l = 1, int r = n) {
    if (l >= ul && r <= ur) {
        add[o] += k, val[o] += k * (r - l + 1);
        return ;
    }
    int mid = (l + r) >> 1, lc = o << 1, rc = lc | 1;
    pushdown(o, lc, rc, r - l + 1);
    if(ul <= mid) upt(ul, ur, k, lc, l, mid);
    if(ur > mid) upt(ul, ur, k, rc, mid + 1, r);
    pushup(o, lc, rc);
}
ll que(int ql, int qr, int o = 1, int l = 1, int r = n) {
    if (l >= ql && r <= qr) return val[o];
    int mid = (l + r) >> 1, lc = o << 1, rc = lc | 1; ll ret = 0;
    pushdown(o, lc, rc, r - l + 1);
    if(ql <= mid) ret = que(ql, qr, lc, l, mid);
    if(qr > mid) ret += que(ql, qr, rc, mid + 1, r);
    return ret;
}

ll sum(int x) {
    int fx = top[x]; ll ret = 0;
    while (fx != 1) ret += que(dfn[fx], dfn[x]), x = fa[fx], fx = top[x];
    return ret + que(1, dfn[x]);
}

int main () {
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; ++i) scanf("%d", c + i);
    for (int i = 1, u, v; i < n; ++i) {
        scanf("%d%d", &u, &v);
        addEdge(u, v), addEdge(v, u);
    }
    dfs1(1), dfs2(1, 1), build();
    while(m--) {
        scanf("%d%d", &opt, &x);
        if (opt == 3) printf("%lld
", sum(x));
        else {
            scanf("%d", &y);
            if (opt == 1) upt(dfn[x], dfn[x], y);
            else upt(dfn[x], dfn[x] + siz[x] - 1, y);
        }
    }
    return 0;
}