Given a rooted tree with 1, supports two modes of operation: to mark a marked point, a point to ask the nearest marked ancestors
Than the board also naked, each marking means that the value is set to this node and all its sub-tree of the current node number
Do not even need up operation, just need to pass the current mark, the next pass when the attention of comparison identification number with the current value
Because it is looking for the closest ancestor, should ensure that the maximum value of depth
Further build operation when the value of all nodes can be set to 1, because the default is marked 1
Code:
#include <bits/stdc++.h> #define int long long #define sc(a) scanf("%lld",&a) #define scc(a,b) scanf("%lld %lld",&a,&b) #define sccc(a,b,c) scanf("%lld %lld %lld",&a,&b,&c) #define schar(a) scanf("%c",&a) #define pr(a) printf("%lld",a) #define fo(i,a,b) for(int i=a;i<b;++i) #define re(i,a,b) for(int i=a;i<=b;++i) #define rfo(i,a,b) for(int i=a;i>b;--i) #define rre(i,a,b) for(int i=a;i>=b;--i) #define prn() printf("\n") #define prs() printf(" ") #define mkp make_pair #define pii pair<int,int> #define pub(a) push_back(a) #define pob() pop_back() #define puf(a) push_front(a) #define pof() pop_front() #define fst first #define snd second #define frt front() #define bak back() #define mem0(a) memset(a,0,sizeof(a)) #define memmx(a) memset(a,0x3f3f,sizeof(a)) #define memmn(a) memset(a,-0x3f3f,sizeof(a)) #define debug #define db double #define yyes cout<<"YES"<<endl; #define nno cout<<"NO"<<endl; using namespace std; typedef vector<int> vei; typedef vector<pii> vep; typedef map<int,int> mpii; typedef map<char,int> mpci; typedef map<string,int> mpsi; typedef deque<int> deqi; typedef deque<char> deqc; typedef priority_queue<int> mxpq; typedef priority_queue<int,vector<int>,greater<int> > mnpq; typedef priority_queue<pii> mxpqii; typedef priority_queue<pii,vector<pii>,greater<pii> > mnpqii; const int maxn=500005; const int inf=0x3f3f3f3f3f3f3f3f; const int MOD=100000007; const db eps=1e-10; int qpow(int a,int b){int tmp=a%MOD,ans=1;while(b){if(b&1){ans*=tmp,ans%=MOD;}tmp*=tmp,tmp%=MOD,b>>=1;}return ans;} int lowbit(int x){return x&-x;} int max(int a,int b){return a>b?a:b;} int min(int a,int b){return a<b?a:b;} int mmax(int a,int b,int c){return max(a,max(b,c));} int mmin(int a,int b,int c){return min(a,min(b,c));} void mod(int &a){a+=MOD;a%=MOD;} bool chk(int now){} int half(int l,int r){while(l<=r){int m=(l+r)/2;if(chk(m))r=m-1;else l=m+1;}return l;} int ll(int p){return p<<1;} int rr(int p){return p<<1|1;} int mm(int l,int r){return (l+r)/2;} int lg(int x){if(x==0) return 1;return (int)log2(x)+1;} bool smleql(db a,db b){if(a<b||fabs(a-b)<=eps)return true;return false;} db len(db a,db b,db c,db d){return sqrt((a-c)*(a-c)+(b-d)*(b-d));} bool isp(int x){if(x==1)return false;if(x==2)return true;for(int i=2;i*i<=x;++i)if(x%i==0)return false;return true;} inline int read() { char ch=getchar();int s=0,w=1; while(ch<48||ch>57){if(ch=='-')w=-1;ch=getchar();} while(ch>=48&&ch<=57){s=(s<<1)+(s<<3)+ch-48;ch=getchar();} return s*w; } inline void write(int x) { if(x<0)putchar('-'),x=-x; if(x>9)write(x/10); putchar(x%10+48); } int head[maxn],to[maxn],e[maxn];//Graph int sz[maxn],fa[maxn],dep[maxn],son[maxn];//using for d1 int ord[maxn],last[maxn];//using for d2 int tg,td,tt;//three timers,using for label graph,dfs and segment tree struct segment_tree{ int l,r,v,tag,ls,rs; }tr[maxn];//segment tree void add(int x,int y){ e[++tg]=y; to[tg]=head[x]; head[x]=tg; } void d1(int x){ sz[x]=1; for(int i=head[x];i;i=to[i]){ int y=e[i]; if(y==fa[x]) continue; fa[y]=x; dep[y]=dep[x]+1; d1(y); sz[x]+=sz[y]; if(sz[y]>sz[son[x]]) son[x]=y; } } void d2(int x){ ord[x]=++td; if(son[x]) d2(son[x]); for(int i=head[x];i;i=to[i]){ int y=e[i]; if(y!=fa[x]&&y!=son[x]) d2(y); } last[x]=td; } void down(int p){ if(tr[p].tag!=0){ if(dep[tr[p].tag]>dep[tr[tr[p].ls].v]){ tr[tr[p].ls].v=tr[p].tag; tr[tr[p].ls].tag=tr[p].tag; } if(dep[tr[p].tag]>dep[tr[tr[p].rs].v]){ tr[tr[p].rs].v=tr[p].tag; tr[tr[p].rs].tag=tr[p].tag; } tr[p].tag=0; } } void build(int x,int y){ ++tt; tr[tt].l=x; tr[tt].r=y; tr[tt].v=1; tr[tt].tag=0; if(x==y){ tr[tt].ls=tr[tt].rs=0; return; } else{ int tmp=tt,m=mm(x,y); tr[tmp].ls=tt+1,build(x,m); tr[tmp].rs=tt+1,build(m+1,y); } } void modify(int p,int x,int y,int z){ if(x<=tr[p].l&&tr[p].r<=y){ if(dep[z]>dep[tr[p].v]){ tr[p].v=z; tr[p].tag=z; } return; } down(p); int m=mm(tr[p].l,tr[p].r); if(x<=m) modify(tr[p].ls,x,y,z); if(y>m) modify(tr[p].rs,x,y,z); } int ask(int p,int pos){ if(tr[p].l==tr[p].r) return tr[p].v; int m=mm(tr[p].l,tr[p].r); down(p); if(pos<=m) return ask(tr[p].ls,pos); else return ask(tr[p].rs,pos); } void modify1(int p,int x,int y){ modify(1,ord[x],last[x],y); } int ask1(int p,int x){ return ask(1,ord[x]); } int n,m,x,y,q; char c; signed main(){ ios_base::sync_with_stdio(0); cin.tie(0),cout.tie(0); cin>>n>>m; re(i,1,n-1){ cin>>x>>y; add(x,y); add(y,x); } d1(1); d2(1); build(1,n); re(i,1,m){ cin>>c>>q; if(c=='C') modify1(1,q,q); else if(c=='Q') cout<<ask1(1,q)<<endl; } return 0; }