初探splay

#include<cctype> #include<cstdio> using namespace std; #define debug(...) fprintf(stderr,__VA_ARGS__) #define DEBUG printf("Passing [%s] in LINE %lld\n",__FUNCTION__,__LINE__) #define Debug debug("Passing [%s] in LINE %lld\n",__FUNCTION__,__LINE__) #define file(FILE_NAME) freopen(FILE_NAME".in","r",stdin),freopen(FILE_NAME".out","w",stdout) #define file_close fclose(stdin),fclose(stdout) #define MAXBUF 2097152 #define FLUSHSIZE 1966080 #define Finline __inline__ __attribute__ ((always_inline)) char BUF[MAXBUF],*P1=BUF,*P2=BUF; Finline int getc(){return P1==P2&&(P2=(P1=BUF)+fread(BUF,1,MAXBUF,stdin),P1==P2)?EOF:*P1++;} inline int read() { int ret = 0,f = 0;char ch = getc(); while(!isdigit (ch)){if(ch == '-') f = 1;ch = getc();} while(isdigit (ch)){ret = ret * 10 + ch - 48;ch = getc();} return f?-ret:ret; } char buf[MAXBUF],print_buf[20];int p,p2=-1; inline void flush(){fwrite(buf,1,p2+1,stdout),p2=-1;} inline void write(int x) { if(p2 > FLUSHSIZE) flush(); if(x<0) buf[++ p2]=45,x = -x; do{print_buf[++ p] = x % 10 + 48;}while(x/=10); do{buf[++p2] = print_buf[p];}while(--p); buf[++p2]='\n'; } const int N = 100005; int rt, tot, fa[N], ch[N][2], val[N], cnt[N], sz[N]; struct SPLAY { inline void maintain(int x){sz[x] = sz[ch[x][0]] + sz[ch[x][1]] + cnt[x];} inline bool get(int x){return x == ch[fa[x]][1];} inline void clear(int x){ch[x][0] = ch[x][1] = fa[x] = val[x] = sz[x] = cnt[x] = 0;} inline void rotate(int x) { int y = fa[x], z = fa[y], chk = get(x); ch[y][chk] = ch[x][chk ^ 1]; fa[ch[x][chk ^ 1]] = y; ch[x][chk ^ 1] = y; fa[y] = x,fa[x] = z; if(z) ch[z][y == ch[z][1]] = x; maintain(x),maintain(y); } void splay(int x) { for(int f = fa[x]; f = fa[x] ,f ; rotate(x)) if(fa[f]) rotate(get(x) == get(f) ? f : x); rt = x; } void insert(int k) { if(!rt) //splay is empty { val[++ tot] = k,cnt[tot] ++;//set point rt = tot,maintain(rt);//set root return; } int cur = rt, f = 0;//insert from rt while(1) { if (val[cur] == k) //find out a point whose value is k { cnt[cur] ++;//size ++ maintain(cur),maintain(f);//update splay(cur);//rotate to root break; } f = cur,cur = ch[cur][val[cur] < k];//find left / right subtree if(!cur)// find a empty position to insert { val[++ tot] = k,cnt[tot]++; fa[tot] = f,ch[f][val[f] < k] = tot; maintain(tot),maintain(f);//update splay(tot); break; } } } int rk(int k) //find k's rank { int res = 0, cur = rt; while(1) { if(k < val[cur]) cur = ch[cur][0];//find left subtree else //find right subtree { res += sz[ch[cur][0]];//add left subtree's size if(k == val[cur])//find out element { splay(cur);//rotate to root return res + 1;//return rank } res += cnt[cur];//add current point value cur = ch[cur][1];//find right subtree } } } int kth(int k) { int cur = rt; while(1) { if(ch[cur][0] && k <= sz[ch[cur][0]]) cur = ch[cur][0]; //find left subtree else { k -= cnt[cur] + sz[ch[cur][0]]; //find right subtree if(k <= 0) return val[cur];//return current point value cur = ch[cur][1];//find right subtree } } } int pre()//find root's predecessor { int cur = ch[rt][0];//find left subtree while(ch[cur][1]) cur = ch[cur][1];//find right subtree return cur; } int nxt() { int cur = ch[rt][1];//find right subtree while (ch[cur][0]) cur = ch[cur][0];//find left subtree return cur; } void del(int k) { rk(k); if(cnt[rt] > 1) //have many same point { cnt[rt]--;//delete one and update maintain(rt); return; } if(!ch[rt][0] && !ch[rt][1]) //have no left / right son { clear(rt);//delete rt = 0; return; } if(!ch[rt][0]) //only have right son { int cur = rt; rt = ch[rt][1]; fa[rt] = 0; clear(cur); return; } if(!ch[rt][1]) //only have left son { int cur = rt; rt = ch[rt][0]; fa[rt] = 0; clear(cur); return; } int x = pre(), cur = rt; splay(x),fa[ch[cur][1]] = x;//right son's father is x's predecessor ch[x][1] = ch[cur][1];//x's predecessor 's right son is x's right son clear(cur),maintain(rt); } }tree; int main() { #ifndef ONLINE_JUDGE file("splay"); #endif int n = read(), opt, x; for(int i = 0;i < n;i ++) { opt = read(),x = read(); if(opt == 1) tree.insert(x); else if(opt == 2) tree.del(x); else if(opt == 3) write(tree.rk(x)); else if(opt == 4) write(tree.kth(x)); else if(opt == 5) tree.insert(x),write(val[tree.pre()]), tree.del(x); else tree.insert(x), write(val[tree.nxt()]),tree.del(x); } flush(); #ifndef ONLINE_JUDGE file_close; #endif return 0; }