HDU 3966 树链剖分后线段树维护

题意:

　　一棵树,

　　操作1.$path(a,b)$之间的点权$+k$

　　操作2.单点查询

题解:

树链剖分即可,注意代码细节,双向映射

主要是记录一下板子

#include <string.h>
#include <stdio.h>
#include <algorithm>
#define endl '\n'
#define ll long long
#define ull unsigned long long
#define fi first
#define se second
#define pii pair<int,int>
#define all(x) x.begin(),x.end()
#define IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define rep(ii,a,b) for(int ii=a;ii<=b;++ii)
#define per(ii,a,b) for(int ii=b;ii>=a;--ii)
#define forn(ii,x) for(int ii=head[x];ii;ii=edge[ii].next)
using namespace std;
const int maxn=5e4+20,maxm=2e6+10;
const int INF=0x3f3f3f3f;
const ll mod=1e9+7;
//head
int casn,n,m,k;
int num[maxn];
class segtree{public:
#define nd node[now]
#define ndl node[now<<1]
#define ndr node[now<<1|1]int node[maxn*4],n;int *mp;void maketree(int s,int t,int now){if(s==t){nd=num[mp[s]];return ;}else nd=0;maketree(s,(s+t)/2,now<<1);maketree((s+t)/2+1,t,now<<1|1);}void init(int nn,int *mps){n=nn;mp=mps;maketree(1,n,1);}void update(int s,int t,int x){update(s,t,x,1,n,1);}int query(int pos){return query(pos,1,n,1);}void update(int s,int t,int x,int l,int r,int now=1){if(s<=l&&t>=r) {nd+=x;return ;}ndl+=nd,ndr+=nd;nd=0;int mid=(l+r)/2;if(s<=mid) update(s,t,x,l,mid,now<<1);if(t>mid) update(s,t,x,mid+1,r,now<<1|1);}int query(int pos,int l,int r,int now=1){if(l==r) return nd;ndl+=nd,ndr+=nd;nd=0;int mid=(l+r)/2;if(pos<=mid) return query(pos,l,mid,now<<1);else  return query(pos,mid+1,r,now<<1|1);}
}tree;
namespace chain{struct data_e{int to,next;}edge[maxn<<1];int head[maxn],nume,mp[maxn];inline void addedge(int a,int b){edge[++nume]={b,head[a]};head[a]=nume;}int ltop[maxn],fa[maxn],deep[maxn];int sz[maxn],remp[maxn];int son[maxn],cnt;void init(){rep(i,1,n) head[i]=0;cnt=0,nume=1;}void dfs1(int now,int pre,int d){deep[now]=d,fa[now]=pre,sz[now]=1,son[now]=0;forn(i,now){int to=edge[i].to;if(to!=pre) {dfs1(to,now,d+1);sz[now]+=sz[to];if(sz[to]>sz[son[now]]) son[now]=to;}}}void dfs2(int now,int pre,int sp){ltop[now]=sp;mp[now]=++cnt;remp[cnt]=now;if(son[now])  dfs2(son[now],now,sp);forn(i,now){int to=edge[i].to;if(to!=son[now]&&to!=pre) dfs2(to,now,to);}}void update(int a,int b,int val){while(ltop[a]!=ltop[b]){if(deep[ltop[a]]<deep[ltop[b]])swap(a,b);tree.update(mp[ltop[a]],mp[a],val);a=fa[ltop[a]];}if(deep[a]>deep[b])swap(a,b);tree.update(mp[a],mp[b],val);}
};int main() {while(~scanf("%d %d %d",&n,&m,&k)){rep(i,1,n) scanf("%d",num+i);chain::init();while(m--){int a,b;scanf("%d%d",&a,&b);chain::addedge(a,b);chain::addedge(b,a);}chain::dfs1(1,0,1);chain::dfs2(1,1,1);tree.init(n,chain::remp);while(k--){char x[10];int a,b,c;scanf("%s",x);if(x[0]=='Q'){scanf("%d",&a);printf("%d\n",tree.query(chain::mp[a]));}else if(x[0]=='I'){scanf("%d %d %d",&a,&b,&c);chain::update(a,b,c);}else {scanf("%d %d %d",&a,&b,&c);chain::update(a,b,-c);}}}
}