Chef and Graph Queries (codechef)

lct维护最大生成树。

 

感觉对于lct的理解不够，整体把握还不好。

 

此题 WAing，待填坑。

 

#include<cstdio>#include<cmath>#include<cstdlib>#include<algorithm> #include<cstring>#include<stack>using namespace std;const int N=400005;int n,m,q,ans[N];int t[N];inline int lowbit(int x){return x&(-x);}void add(int i,int p) {for (;i<=m;i+=lowbit(i)) t[i]+=p;}int sum(int i){int ans=0;for (;i;i-=lowbit(i)) ans+=t[i];return ans;}struct aa{int a,b,id;bool operator <(const aa &c) const {return b<c.b;}}Q[N],bian[N];int fa[N],ch[N][2],rev[N],val[N],mi[N],id[N];stack<int> s;bool isroot(int x){return ch[fa[x]][0]!=x&&ch[fa[x]][1]!=x;}void up(int x){mi[x]=val[x],id[x]=x;if (ch[x][0]&&mi[ch[x][0]]<mi[x]) mi[x]=mi[ch[x][0]],id[x]=id[ch[x][0]];if (ch[x][1]&&mi[ch[x][1]]<mi[x]) mi[x]=mi[ch[x][1]],id[x]=id[ch[x][1]];}void down(int x){if (rev[x]){rev[x]^=1,rev[ch[x][0]]^=1,rev[ch[x][1]]^=1;swap(ch[x][0],ch[x][1]);}}void rot(int x){int y=fa[x],z=fa[y],l,r;if (ch[y][0]==x) l=0;else l=1;r=l^1;if (!isroot(y))if (ch[z][0]==y) ch[z][0]=x;else ch[z][1]=x;fa[x]=z,fa[y]=x,fa[ch[x][r]]=y;ch[y][l]=ch[x][r],ch[x][r]=y;up(y);}void splay(int x){int y=x,z;while (!isroot(y)) s.push(y),y=fa[y];s.push(y);while (!s.empty()) down(s.top()),s.pop();while (!isroot(x)){y=fa[x],z=fa[y];if (!isroot(y))if (ch[y][0]==x^ch[z][0]==y) rot(x);else rot(y);rot(x);}up(x);}void access(int x){int t=0;while (x){splay(x);down(x);ch[x][1]=t;up(x);t=x,x=fa[x];}}int find(int x){access(x),splay(x);while (ch[x][0]) x=ch[x][0];return x;}void to_rt(int x){access(x),splay(x),rev[x]^=1;}void link(int x,int y){to_rt(x),fa[x]=y;}void cut(int x,int y){to_rt(x),access(y),splay(y);ch[y][0]=fa[x]=0;up(y);}int find_mi(int u,int v){to_rt(u),access(v),splay(v);return id[v];}void addedge(int ii){int u=bian[ii].a,v=bian[ii].b,fu,fv;if (u==v) return ;fu=find(u),fv=find(v);add(ii,1);if (fu!=fv) {link(u,n+ii);link(v,n+ii);return ;}int pos=find_mi(u,v)-n;add(pos,-1);cut(pos+n,bian[pos].a);cut(pos+n,bian[pos].b);link(ii+n,u);link(ii+n,v);}void clear(){for (int i=1;i<=m;i++) t[i]=0;for (int i=1;i<=n+m;i++) fa[i]=ch[i][0]=ch[i][1]=rev[i]=id[i]=mi[i]=0;}int main(){int T,x,y;scanf("%d",&T);while (T--){scanf("%d%d%d",&n,&m,&q);for (int i=1;i<=n;i++) mi[i]=val[i]=1e8,id[i]=i;for (int i=1;i<=m;i++)scanf("%d%d",&bian[i].a,&bian[i].b),mi[i+n]=val[n+i]=i,id[i+n]=i+n;for (int i=1;i<=q;i++) scanf("%d%d",&Q[i].a,&Q[i].b),Q[i].id=i;sort(Q+1,Q+q+1);int j=1;for (int i=1;i<=m;i++){addedge(i);for (;Q[j].b==i;j++)ans[Q[j].id]=n-(sum(m)-sum(Q[j].a-1));}for (int i=1;i<=q;i++) printf("%d\n",ans[i]);clear();}return 0;}/*23 5 41 31 22 13 22 22 31 55 51 21 1 11 11 1*/