洛谷 P2590 [ZJOI2008]树的统计

题目传送门

跟板子差不多

AC代码:

#include<iostream>
#include<cstdio>
#include<cstring>

using namespace std;

int n,head[30001],tot,w[30001],rk[30001],p;
long long ans;
struct kkk {
    int to,next;
}e[60001];
struct poufen {
    int deep,f,si,son,top,id;
}q[30001];
struct xianduanshu {
    int l,r,v,mm,lazy;
}a[120001];

inline void add(int x,int y) {
    e[++tot].to = y;
    e[tot].next = head[x];
    head[x] = tot;
}

inline void dfs1(int rt,int fa,int d) {
    q[rt].deep = d;
    q[rt].f = fa;
    q[rt].si = 1;
    q[rt].son = 0;
    for(int i = head[rt];i; i = e[i].next) {
        int u = e[i].to;
        if(u == fa) continue;
        dfs1(u,rt,d + 1);
        q[rt].si += q[u].si;
        if(q[q[rt].son].si < q[u].si) q[rt].son = u;
    }
}

inline void dfs2(int rt,int topf) {
    q[rt].top = topf;
    q[rt].id = ++tot;
    rk[tot] = rt;
    if(q[rt].son == 0) return ;
    dfs2(q[rt].son,topf);
    for(int i = head[rt];i; i = e[i].next) {
        int u = e[i].to;
        if(u == q[rt].son || u == q[rt].f) continue;
        dfs2(u,u);
    }
}

inline int max(int uu,int oo) {
    if(uu > oo) return uu;
    return oo;
}

inline long long max1(long long uu,int oo) {
    if(uu > oo) return uu;
    return oo;
}

inline void build(int rt,int ll,int rr) {
    a[rt].l = ll;
    a[rt].r = rr;
    if(ll == rr) {
        a[rt].v = w[rk[ll]];
        a[rt].mm = a[rt].v;
        return ;
    }
    int mid = (ll + rr) >> 1;
    build(rt * 2,ll,mid);
    build(rt * 2 + 1,mid + 1,rr);
    a[rt].v = a[rt*2].v + a[rt*2+1].v;
    a[rt].mm = max(a[rt*2].mm,a[rt*2+1].mm);
}

inline void change(int rt,int l,int len) {
    if(a[rt].l == l && a[rt].r == l) {
        a[rt].v = len;
        a[rt].mm = len;
        return ;
    }
    int mid = (a[rt].l + a[rt].r) >> 1;
    if(l <= mid) change(rt * 2,l,len);
    else change(rt * 2 + 1,l,len);
    a[rt].v = a[rt*2].v + a[rt*2+1].v;
    a[rt].mm = max(a[rt*2].mm,a[rt*2+1].mm);
}

inline void find_max(int rt,int L,int R) {
    if(a[rt].l >= L && a[rt].r <= R) {
        ans = max1(ans,a[rt].mm);
        return ;
    }
    int mid = (a[rt].l + a[rt].r) >> 1;
    if(L <= mid) find_max(rt * 2,L,R);
    if(R > mid) find_max(rt*2+1,L,R);
}

inline void treefind(int x,int y) {
    int tx = q[x].top;
    int ty = q[y].top;
    while(ty != tx) {
        if(q[tx].deep >= q[ty].deep) {
            find_max(1,q[tx].id,q[x].id);
            x = q[tx].f;tx = q[x].top;
        }
        else {
            find_max(1,q[ty].id,q[y].id);
            y = q[ty].f;ty = q[y].top;
        }
    }
    if(q[x].deep >= q[y].deep) 
        find_max(1,q[y].id,q[x].id);
    else
        find_max(1,q[x].id,q[y].id);
}

inline int qiuhe(int rt,int L,int R) {
    int pp = 0;
    if(a[rt].l >= L && a[rt].r <= R)
        return a[rt].v;
    int mid = (a[rt].l + a[rt].r) >> 1;
    if(L <= mid) pp += qiuhe(rt * 2,L,R);
    if(R > mid) pp += qiuhe(rt * 2 + 1,L,R);
    return pp;
} 

inline int treesum(int x,int y) {
    int tx = q[x].top;
    int ty = q[y].top;
    int daan = 0;
    while(ty != tx) {
        if(q[tx].deep > q[ty].deep) {
            daan += qiuhe(1,q[tx].id,q[x].id);
            x = q[tx].f;tx = q[x].top;
        }
        else {
            daan += qiuhe(1,q[ty].id,q[y].id);
            y = q[ty].f;ty = q[y].top;
        }
    }
    if(q[x].deep >= q[y].deep) 
        daan += qiuhe(1,q[y].id,q[x].id);
    else
        daan += qiuhe(1,q[x].id,q[y].id);
    return daan;
}
//
//inline void PPPP(int r) {
//    if(a[r].l == a[r].r) {
//        printf("%d ",a[r].mm);
//        return ;
//    }
//    PPPP(r*2);
//    PPPP(r*2+1);
//}

int main() {
    scanf("%d",&n);
    for(int i = 1;i <= n - 1; i++) {
        int x,y;
        scanf("%d%d",&x,&y);
        add(x,y);
        add(y,x);
    }
    for(int i = 1;i <= n; i++)
        scanf("%d",&w[i]);
    dfs1(1,0,1);
    tot = 0;
    dfs2(1,1);
    build(1,1,n);
    scanf("%d",&p);
    for(int i = 1;i <= p; i++) {
        string r;
        cin >> r;
        if(r == "CHANGE") {
            int x,y;
            scanf("%d%d",&x,&y);
            change(1,q[x].id,y);
            //PPPP(1);
        }
        if(r == "QMAX") {
            int x,y;
            ans = -10000000000;
            scanf("%d%d",&x,&y);
            treefind(x,y);
            printf("%lld
",ans);
        }
        if(r == "QSUM") {
            int x,y;
            scanf("%d%d",&x,&y);
            printf("%d
",treesum(x,y));
        }
    }
    return 0;
}