83: 模拟赛 树形dp

$des$

$sol$

维护每个点的子树中的信息以及非子树的信息

$code$

#include <bits/stdc++.h>

using namespace std;

#define gc getchar()
inline int read() {
    int x = ; char c = gc;
    while(c < '' || c > '') c = gc;
    while(c >= '' && c <= '') x = x *  + c - '', c = gc;
    return x;
}

#define Rep(i, a, b) for(int i = a; i <= b; i ++)

const int N = 1e5 + ;

int f[N][], g[N][];
int n, p;
int deep[N], fa[N], size[N][], sizeg[N][];

struct Node {
    int v, w, nxt;
} G[N << ];
int cnt, head[N];

void Link(int u, int v, int w) {
    G[++ cnt].v = v, G[cnt].w = w, G[cnt].nxt = head[u]; head[u] = cnt;
}

void Dfs1(int u, int f_, int dep) {
    deep[u] = dep, fa[u] = f_;
    for(int i = head[u]; ~ i; i = G[i].nxt) {
        int v = G[i].v;
        if(v == f_) continue;
        Dfs1(v, u, dep + );
    }
}

void Dfs2(int u) {
    for(int i = head[u]; ~ i; i = G[i].nxt) {
        int v = G[i].v, w = G[i].w;
        if(v == fa[u]) continue;
        Dfs2(v);
        if(w % ) {
            size[u][] += size[v][];
            size[u][] += size[v][];
            size[u][] ++;
            f[u][] += f[v][] + w * size[v][];
            f[u][] += f[v][] + w * size[v][] + w;
        } else {
            size[u][] += size[v][];
            size[u][] += size[v][];
            size[u][] ++;
            f[u][] += f[v][] + w * size[v][] + w;
            f[u][] += f[v][] + w * size[v][];
        }
    }
}

void Dfs3(int u) {
    for(int i = head[u]; ~ i; i = G[i].nxt) {
        int v = G[i].v, w = G[i].w;
        if(v == fa[u]) continue;
        if(w % ) {
            sizeg[v][] ++;
            sizeg[v][] += sizeg[u][] + size[u][] - size[v][];
            sizeg[v][] += sizeg[u][] + size[u][] - size[v][] - ;
            g[v][] += g[u][] + (f[u][] - f[v][]) - size[v][] * w;
            g[v][] += w * (sizeg[u][] + size[u][] - size[v][] + );
            g[v][] += g[u][] + (f[u][] - f[v][]) - size[v][] * w - w;
            g[v][] += w * (sizeg[u][] + size[u][] - size[v][] - );
        } else {
            sizeg[v][] ++;
            sizeg[v][] += sizeg[u][] + size[u][] - size[v][];
            sizeg[v][] += sizeg[u][] + size[u][] - size[v][] - ;
            g[v][] += g[u][] + (f[u][] - f[v][]) - size[v][] * w;
            g[v][] += w * (sizeg[u][] + size[u][] - size[v][]);
            g[v][] += g[u][] + (f[u][] - f[v][]) - size[v][] * w - w;
            g[v][] += w * (sizeg[u][] + size[u][] - size[v][] +  - );
        }
        Dfs3(v);
    }
}

int main() {
    n = read(), p = read();
    Rep(i, , n) head[i] = -;
    Rep(i, , n - ) {
        int u = read(), v = read(), w = read();
        Link(u, v, w), Link(v, u, w);
    }
    Dfs1(, , );
    Dfs2();
    Dfs3();
    Rep(pp, , p) {
        int x = read();
        int j = f[x][] + g[x][];
        int o = f[x][] + g[x][];
        cout << j << " " << o << "\n";
    }

    return ;
}