【BZOJ 3224】 普通平衡树

【题目链接】

点击打开链接

【算法】

本题是Splay模板题，值得一做！

【代码】

#include<bits/stdc++.h>
using namespace std;
#define MAXN 100000

int N,opt,x;

template <typename T> inline void read(T &x) {
        int f = ; x = ;
        char c = getchar();
        for (; !isdigit(c); c = getchar()) { if (c == '-') f = -f; }
        for (; isdigit(c); c = getchar()) x = (x << ) + (x << ) + c - '';
        x *= f;
}

template <typename T> inline void write(T x) {
    if (x < ) { putchar('-'); x = -x; }
    if (x > ) write(x/);
    putchar(x%+'');
}

template <typename T> inline void writeln(T x) {
    write(x);
    puts("");
}

struct Splay {
        int root,total;
        struct Node {
                int fa,son[],val,cnt,size;
        } Tree[MAXN+];
        bool get(int x) {
                return Tree[Tree[x].fa].son[] == x;
        }
        inline void new_node(int index,int f,int x) {
                Tree[index].fa = f;
                Tree[index].son[] = Tree[index].son[] = ;
                Tree[index].val = x;
                Tree[index].cnt = Tree[index].size = ;
        }
        inline void update(int index) {
                Tree[index].size = Tree[index].cnt;
                Tree[index].size += Tree[Tree[index].son[]].size;
                Tree[index].size += Tree[Tree[index].son[]].size;
        }
        inline void rotate(int x) {
                int f = Tree[x].fa,g = Tree[f].fa,
                    tmpx = get(x),tmpf = get(f);
                if (!f) return;
                Tree[f].son[tmpx] = Tree[x].son[tmpx^];
                if (Tree[x].son[tmpx^]) Tree[Tree[x].son[tmpx^]].fa = f;
                Tree[x].son[tmpx^] = f;
                Tree[f].fa = x;
                Tree[x].fa = g;
                if (g) Tree[g].son[tmpf] = x;
                update(f);
                update(x);
        }
        inline void splay(int x) {
                int f;
                for (f = Tree[x].fa; (f = Tree[x].fa); rotate(x))
                        rotate((get(x) == get(f)) ? (f) : (x));
                root = x;
        }
        inline void Insert(int x) {
                int index = root;
                bool tmp;
                if (!root) {
                        new_node(++total,,x);
                        root = total;
                        return;
                }
                while (true) {
                        if (Tree[index].val == x) {
                                ++Tree[index].cnt;
                                splay(index);
                                return;
                        }
                        tmp = Tree[index].val < x;
                        if (!Tree[index].son[tmp]) {
                                new_node(++total,index,x);
                                Tree[index].son[tmp] = total;
                                splay(total);
                                return;
                        } else index = Tree[index].son[tmp];
                }
        }
        inline int query_max(int index) {
                while (true) {
                        if (!Tree[index].son[]) return index;
                        index = Tree[index].son[];
                }
        }
        inline int query_min(int index) {
                while (true) {
                        if (!Tree[index].son[]) return index;
                        index = Tree[index].son[];
                }
        }
        inline void join(int x,int y) {
                int pos = query_max(x);
                splay(pos);
                Tree[pos].son[] = y;
                Tree[y].fa = pos;
        }
        inline void erase(int x) {
                int index = root;
                bool tmp;
                while (true) {
                        if (Tree[index].val == x) {
                                if (Tree[index].cnt > ) {
                                        --Tree[index].cnt;
                                        splay(index);
                                        return;
                                }
                                splay(index);
                                break;
                        }
                        tmp = Tree[index].val < x;
                        index = Tree[index].son[tmp];
                }
                if ((!Tree[index].son[]) && (!Tree[index].son[])) {
                        root = ;
                        return;
                }
                if (!Tree[index].son[]) {
                        root = Tree[index].son[];
                        Tree[root].fa = ;
                        return;
                }
                if (!Tree[index].son[]) {
                        root = Tree[index].son[];
                        Tree[root].fa = ;
                        return;
                }
                join(Tree[index].son[],Tree[index].son[]);
        }
        inline int query_rank(int x) {
                int index = root,ans=;
                while (true) {
                        if (Tree[index].val <= x) {
                                ans += Tree[Tree[index].son[]].size;
                                if (Tree[index].val == x) {
                                        splay(index);
                                        return ans;
                                }
                                ans += Tree[index].cnt;
                                index = Tree[index].son[];
                        } else index = Tree[index].son[];
                }
        }
        inline int rank(int x) {
                int index = root;
                while (true) {
                        if (x <= Tree[Tree[index].son[]].size) index = Tree[index].son[];
                        else {
                                x -= Tree[Tree[index].son[]].size;
                                if (x <= Tree[index].cnt) {
                                        splay(index);
                                        return Tree[index].val;
                                }
                                x -= Tree[index].cnt;
                                index = Tree[index].son[];
                        }
                }
        }
        inline int pred(int x) {
                int ans;
                Insert(x);
                ans = Tree[query_max(Tree[root].son[])].val;
                erase(x);
                return ans;
        }
        inline int succ(int x) {
                int ans;
                Insert(x);
                ans = Tree[query_min(Tree[root].son[])].val;
                erase(x);
                return ans;
        }
} T;

int main() {
        read(N);
        while (N--) {
                read(opt); read(x);
                if (opt == ) T.Insert(x);
                else if (opt == ) T.erase(x);
                else if (opt == ) writeln(T.query_rank(x));
                else if (opt == ) writeln(T.rank(x));
                else if (opt == ) writeln(T.pred(x));
                else if (opt == ) writeln(T.succ(x));
        }

        return ;

}