【LOJ】#3036. 「JOISC 2019 Day3」指定城市

LOJ#3036. 「JOISC 2019 Day3」指定城市

一个点的可以dp出来

两个点也可以dp出来

后面的就是在两个点的情况下选一条最长的链加进去，用线段树维护即可

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define eps 1e-10
#define MAXN 200005
#define ba 47
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
    res = 0;T f = 1;char c = getchar();
    while(c < '0' || c > '9') {
    	if(c == '-') f = -1;
    	c = getchar();
    }
    while(c >= '0' && c <= '9') {
    	res = res * 10 +c - '0';
    	c = getchar();
    }
    res *= f;
}
template<class T>
void out(T x) {
    if(x < 0) {x = -x;putchar('-');}
    if(x >= 10) {
    	out(x / 10);
    }
    putchar('0' + x % 10);
}
struct node {
    int to,next;int64 val;
}E[MAXN * 2];
int head[MAXN],sumE,N;
int64 ans[MAXN],all;
void add(int u,int v,int c) {
    E[++sumE].to = v;
    E[sumE].next = head[u];
    E[sumE].val = c;
    head[u] = sumE;
}
namespace one {
    int64 dis[2][MAXN],fir;
    void dfs(int u,int fa) {
        for(int i = head[u] ; i ; i = E[i].next) {
            int v = E[i].to;
            if(v == fa) {dis[1][u] = dis[1][fa] + E[i].val;fir += E[i].val;}
            else dis[0][v] = dis[0][u] + E[i].val;
        }
        for(int i = head[u] ; i ; i = E[i].next) {
            int v = E[i].to;
            if(v != fa) dfs(v,u);
        }
    }
    void Main() {
        dfs(1,0);
        int64 res = fir;
        for(int i = 2 ; i <= N ; ++i) {
            res = max(res,fir + dis[0][i] - dis[1][i]);
        }
        ans[1] = all - res;
    }
}
namespace two {
    int64 dis[2][MAXN],fir,mval = 0;
    pair<int64,int> dp[MAXN];
    int siz[MAXN],dfn[MAXN],idx,line[MAXN],fa[MAXN],S = 1,T = 1;
    bool vis[MAXN];
    struct node {
        int l,r,pos;int64 mv,lz;
    }tr[MAXN * 4];
    void dfs(int u) {
        siz[u] = 1;dfn[u] = ++idx;line[idx] = u;
        for(int i = head[u] ; i ; i = E[i].next) {
            int v = E[i].to;
            if(v == fa[u]) {dis[1][u] = dis[1][fa[u]] + E[i].val;fir += E[i].val;}
            else dis[0][v] = dis[0][u] + E[i].val;
        }
        dp[u] = mp(0,u);
        for(int i = head[u] ; i ; i = E[i].next) {
            int v = E[i].to;
            if(v != fa[u]) {
                fa[v] = u;
                dfs(v);
                siz[u] += siz[v];
                if(E[i].val + dp[v].fi + dp[u].fi - dis[1][u] + dis[0][u] > mval) {
                    mval = E[i].val + dp[v].fi + dp[u].fi - dis[1][u] + dis[0][u];
                    S = dp[u].se;T = dp[v].se;
                }
                if(dp[v].fi + E[i].val > dp[u].fi) {
                    dp[u].fi = dp[v].fi + E[i].val;dp[u].se = dp[v].se;
                }
            }
        }
    }
    void update(int u) {
        if(tr[u << 1].mv > tr[u << 1 | 1].mv) {
            tr[u].mv = tr[u << 1].mv;
            tr[u].pos = tr[u << 1].pos;
        }
        else {
            tr[u].mv = tr[u << 1 | 1].mv;
            tr[u].pos = tr[u << 1 | 1].pos;
        }
    }
    void addlz(int u,int64 v) {
        tr[u].mv += v;tr[u].lz += v;
    }
    void pushdown(int u) {
        if(tr[u].lz) {
            addlz(u << 1,tr[u].lz);
            addlz(u << 1 | 1,tr[u].lz);
            tr[u].lz = 0;
        }
    }
    void build(int u,int l,int r) {
        tr[u].l = l;tr[u].r = r;
        if(l == r) {
            tr[u].mv = dis[0][line[l]];tr[u].pos = line[l];
            return;
        }
        int mid = (l + r) >> 1;
        build(u << 1,l,mid);
        build(u << 1 | 1,mid + 1,r);
        update(u);
    }
    void Add(int u,int l,int r,int64 v) {
        if(tr[u].l == l && tr[u].r == r) {addlz(u,v);return;}
        pushdown(u);
        int mid = (tr[u].l + tr[u].r) >> 1;
        if(r <= mid) Add(u << 1,l,r,v);
        else if(l > mid) Add(u << 1 | 1,l,r,v);
        else {Add(u << 1,l,mid,v);Add(u << 1 | 1,mid + 1,r,v);}
        update(u);
    }
    int64 Query(int u,int pos) {
        if(tr[u].l == tr[u].r) return tr[u].mv;
        pushdown(u);
        int mid = (tr[u].l + tr[u].r) >> 1;
        if(pos <= mid) return Query(u << 1,pos);
        else return Query(u << 1 | 1,pos);
    }
    void Delete(int u) {
        int pre = 0;
        while(u && !vis[u]) {
            int64 t = Query(1,dfn[u]);
            if(!pre) Add(1,dfn[u],dfn[u] + siz[u] - 1,-t);
            else {
                Add(1,dfn[u],dfn[pre] - 1,-t);
                if(dfn[pre] + siz[pre] <= dfn[u] + siz[u] - 1)
                    Add(1,dfn[pre] + siz[pre],dfn[u] + siz[u] - 1,-t);
            }
            vis[u] = 1;
            pre = u;u = fa[u];
        }
    }
    void More(int x) {
        ans[x] = ans[x - 1] - tr[1].mv;
        Delete(tr[1].pos);
    }
    void Main() {
        dfs(1);
        ans[2] = all - (fir + mval);
        memset(dis,0,sizeof(dis));
        fa[S] = 0;idx = 0;
        dfs(S);
        build(1,1,N);
        Delete(T);
    }
}
void Solve() {
    read(N);
    int a,b,c,d;
    for(int i = 1 ; i < N ; ++i) {
        read(a);read(b);read(c);read(d);
        add(a,b,c);
        add(b,a,d);
        all += c;all += d;
    }
    one::Main();
    if(N >= 2) two::Main();
    for(int i = 3 ; i <= N ; ++i) {
        two::More(i);
    }
    int Q;
    read(Q);
    for(int i = 1 ; i <= Q ; ++i) {
        read(a);
        out(ans[a]);enter;
    }
}
int main() {
#ifdef ivorysi
    freopen("f1.in","r",stdin);
#endif
    Solve();
    return 0;
}