Bzoj1251, 1251 Road

Bzoj1251, 1251 Road

Splay template question.

Use splay to maintain the sequence, so that the intermediate order traversal of splay is this sequence. When processing [l, r], L-1 to the root, then rotate r + 1 to the right subtree of the root, then the left subtree of the right subtree of the root is [l, r.

Code:

  1 #include<iostream>  2 #include<cstdio>  3 #include<cstring>  4 using namespace std;  5 #define N 50010  6 #define INF 2147483647  7 bool b[N];  8 int i,j,k,m,n,c[N],s[N],a[N],Rt,p[N],ch[N][2],f[N],x,y,z;  9 inline int Get(int x){return ch[f[x]][1]==x;} 10 inline int _Max(int x,int y){return x>y?x:y;} 11 inline void Up(int x){ 12     c[x]=_Max(a[x],_Max(c[ch[x][0]],c[ch[x][1]])); 13     s[x]=s[ch[x][0]]+s[ch[x][1]]+1; 14 } 15 inline void Down(int x){ 16     if(!x)return; 17     if(p[x]){ 18         if(ch[x][0])p[ch[x][0]]+=p[x],c[ch[x][0]]+=p[x],a[ch[x][0]]+=p[x]; 19         if(ch[x][1])p[ch[x][1]]+=p[x],c[ch[x][1]]+=p[x],a[ch[x][1]]+=p[x]; 20         p[x]=0; 21     } 22     if(b[x]){ 23         int t=ch[x][0];ch[x][0]=ch[x][1];ch[x][1]=t; 24         if(ch[x][0])b[ch[x][0]]^=1; 25         if(ch[x][1])b[ch[x][1]]^=1; 26         b[x]=0; 27     } 28 } 29 inline void Rotate(int x){ 30     int y=f[x];bool d=Get(x); 31     ch[f[y]][Get(y)]=x; 32     f[x]=f[y]; 33     ch[y][d]=ch[x][d^1]; 34     f[ch[y][d]]=y; 35     ch[x][d^1]=y; 36     f[y]=x;Up(y); 37 } 38 inline void Splay(int x,int g){ 39     while(f[x]!=g){ 40         Down(f[f[x]]);Down(f[x]);Down(x); 41         if(f[f[x]]){ 42             if(f[f[x]]==g){Rotate(x);break;} 43             Rotate(Get(x)==Get(f[x])?f[x]:x); 44         } 45         Rotate(x); 46     } 47     Up(x); 48     if(!g)Rt=x; 49 } 50 inline int Search(int x){ 51     int u=Rt; 52     Down(u); 53     while(s[ch[u][0]]!=x){ 54         if(s[ch[u][0]]>x)u=ch[u][0];else x-=s[ch[u][0]]+1,u=ch[u][1]; 55         Down(u); 56     } 57     return u; 58 } 59 inline int Build(int l,int r){ 60     if(l>r)return 0; 61     if(l==r)return l; 62     int Mid=l+r>>1; 63     ch[Mid][0]=Build(l,Mid-1); 64     ch[Mid][1]=Build(Mid+1,r); 65     s[Mid]=s[ch[Mid][0]]+s[ch[Mid][1]]+1; 66     f[ch[Mid][0]]=f[ch[Mid][1]]=Mid; 67     Up(Mid); 68     return Mid; 69 } 70 inline void Update(int l,int r,int x){ 71     int u=Search(l-1),v=Search(r+1); 72     Splay(u,0);Splay(v,u); 73     c[ch[v][0]]+=x; 74     p[ch[v][0]]+=x; 75     a[ch[v][0]]+=x; 76 } 77 inline void Reverse(int l,int r){ 78     int u=Search(l-1),v=Search(r+1); 79     Splay(u,0);Splay(v,u); 80     b[ch[v][0]]^=1; 81 } 82 inline int Query(int l,int r){ 83     int u=Search(l-1),v=Search(r+1); 84     Splay(u,0);Splay(v,u); 85     return c[ch[v][0]]; 86 } 87 inline void Init(){ 88     for(int i=1;i<=n+2;i++)s[i]=1; 89     c[0]=a[0]=-INF;c[1]=a[1]=-INF; 90     c[n+2]=a[n+2]=-INF; 91     Rt=Build(1,n+2); 92     ch[0][0]=Rt; 93 } 94 int main() 95 { 96     scanf("%d%d",&n,&m); 97     Init(); 98     while(m--){ 99         scanf("%d",&k);100         if(k==1)scanf("%d%d%d",&x,&y,&z),Update(x,y,z);else{101             scanf("%d%d",&x,&y);102             if(k==2)Reverse(x,y);else printf("%d\n",Query(x,y));103         }104     }105     return 0;106 }

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