個人賽C 檸檬樹2--樹鏈剖分+維護最值出現次數/LCA

給一棵樹，維護上面兩點最短路徑中結點的最大值及最大值出現次數

#include <stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
const int maxn = 300010+10;
#define inf 1000000005
typedef pair<int,int>pii;
int w[maxn];
int N, Q;


struct
{
    int to,next,w;    
}e[maxn<<2];

int head[maxn<<1],edgeNum;

struct
{
	int u,v;
}edge[maxn<<1];

void add(int u,int v)
{
    e[edgeNum].next = head[u];
    e[edgeNum].to = v;
   // e[edgeNum].w=w;
    head[u] = edgeNum++;
}

/*-------------------------樹剖------------------------------*/
int deep[maxn],fa[maxn],siz[maxn],son[maxn];
void dfs1(int u,int pre,int d)
{
    deep[u] = d;
    fa[u] = pre;
    siz[u] = 1;
    son[u] = 0;
    for(int i=head[u];~i;i=e[i].next)
    {
        int v = e[i].to;
        if(v!=pre)
        {
            dfs1(v,u,d+1);
            siz[u] += siz[v];
            if(siz[v]>siz[son[u]])
                son[u] = v;
        }
    }
}

int top[maxn],id[maxn],rk[maxn],cnt;

void dfs2(int u,int t)
{
    top[u] = t;
    id[u] = ++cnt;
    rk[cnt] = u;
    if(!son[u]) return;

    dfs2(son[u],t);

    for(int i=head[u];~i;i=e[i].next)
    {
        int v = e[i].to;
        if(v!=son[u]&&v!=fa[u])
            dfs2(v,v);
    }
}
/*-------------------------樹剖------------------------------*/

/*-------------------------線段樹------------------------------*/
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
int sum[maxn<<2],maxv[maxn<<2],lazy[maxn<<2],ci[maxn<<2];
void pushup(int rt)
{
	if(maxv[rt<<1]>maxv[rt<<1|1]){
		sum[rt]=sum[rt<<1];
	}
	else if(maxv[rt<<1]<maxv[rt<<1|1])sum[rt]=sum[rt<<1|1];
    else sum[rt] = (sum[rt<<1] + sum[rt<<1|1]);
    maxv[rt] =max(maxv[rt<<1],maxv[rt<<1|1]);
}


void change(int val,int q,int l,int r,int rt)//單點更新 
{
    if(l==r)
    {
        sum[rt]=1;//出現次數 
        maxv[rt]=val;
        return ;
    }
    int m = l + r >> 1;
    if(q<=m)
        change(val,q,lson);
    else
        change(val,q,rson);
    pushup(rt);
}


pii query(int L,int R,int l,int r,int rt)
{
    if(L<=l&&r<=R)
        return {maxv[rt],sum[rt]};
    int m = l + r >> 1;
	pii a={0,0},b={0,0},ans;
    if (L<=m)a=query(L,R,lson);
    if (R>m)b=query(L,R,rson);
    if(a.first==b.first)ans={a.first,a.second+b.second};
    else if(a.first<b.first)ans=b;
    else ans=a;
    
    return ans;
}

int querymax(int L,int R,int l,int r,int rt){
    if (L<=l&&r<=R)return maxv[rt];
    int m=(l+r)>>1,ans=-inf;//注意負數① 
    if (L<=m)ans=max(ans,querymax(L,R,lson));
    if (R>m)ans=max(ans,querymax(L,R,rson));
    //pushup(rt);
    return ans;
}
/*-------------------------線段樹------------------------------*/

/*-----------------------樹剖加線段樹--------------------------*/

pii query(int x,int y)
{
    pii ans = {-2,-2};
    while(top[x] != top[y])
    {
        if(deep[top[x]] < deep[top[y]])
            swap(x,y);
            
        pii tmp = query(id[top[x]],id[x],1,cnt,1); 
        if(tmp.first==ans.first)ans={tmp.first,tmp.second+ans.second};
        else if(tmp.first>ans.first)ans=tmp;
        
        x = fa[top[x]];
    }
    if(deep[x]>deep[y])
        swap(x,y);
        
      pii tmp = query(id[x],id[y],1,cnt,1); 
        if(tmp.first==ans.first)ans={tmp.first,tmp.second+ans.second};
        else if(tmp.first>ans.first)ans=tmp;
        
    return ans;
}

int querymax(int x,int y)
{
    int ans =-inf;//注意負數② 
    while(top[x] != top[y])
    {
        if(deep[top[x]] < deep[top[y]])
            swap(x,y);
        ans = max(ans ,querymax(id[top[x]],id[x],1,cnt,1)); 
        x = fa[top[x]];
    }
    if(deep[x]>deep[y])
        swap(x,y);
    ans = max(ans ,querymax(id[x],id[y],1,cnt,1));
    return ans;
}
/*-----------------------樹剖加線段樹--------------------------*/

void init()
{
    memset(head,-1,4*N+4);
    cnt = edgeNum = 0;
}

int u, v, o,z,cur;
int main()
{   
   
		scanf("%d",&N);
   	    init();
   	    for(int i=1;i<=N;i++)scanf("%d",&w[i]);
   	for(int i=1;i<N;++i)
	{
		//w[i] = 0;
		scanf("%d%d",&u,&v);
//		edge[i].u=u,edge[i].v=v;//真正的邊數 
		add(u,v);//邊數*2 
		add(v,u);
		
	}
	
	dfs1(1,0,1);
	dfs2(1,1);
	for(int i=1;i<=N;i++){
		change(w[i],id[i],1,N,1);
	}
	scanf("%d",&Q);
//	build(1,cnt,1);
	while(Q--)
	{
			scanf("%d%d",&o,&z);
			pii res=query(o,z);
			printf("%d %d\n",res.first,res.second);

	}
	   

    return 0;
}

感謝睿明鍋，lca做法待更