传送门
Splay的区间翻转:若要翻转[l, r],将l-1 Splay到根,将r+1 Splay到l-1的右儿子,然后[l, r]就在r+1的左儿子的位置了,给它打上标记,完工!
哦,写的时候一定要注意随时pushdown,以免出错.

数组版

/**************************************************************
    Problem: 3223
    User: geng4512
    Language: C++
    Result: Accepted
    Time:1868 ms
    Memory:4712 kb
****************************************************************/

#include<cstdio>
#define MAXN 200005
int tmp;
inline void Swap(int &a, int &b) { tmp = a; a = b; b = tmp; }
struct node {
    int sz, ch[2], f; bool rev;
    inline void mt() {
        Swap(ch[0], ch[1]);
    }
}t[MAXN];
int rt, sz, n, m;
#define Upd(r) {t[r].sz = t[t[r].ch[0]].sz + t[t[r].ch[1]].sz + 1;}
void rot(int x)
{
    int y = t[x].f, z = t[y].f;
    bool f = (t[y].ch[1] == x);
    t[y].ch[f] = t[x].ch[f^1];
    if(t[y].ch[f]) t[t[y].ch[f]].f = y;
    t[x].ch[f^1] = y; t[y].f = x;
    t[x].f = z;
    if(z) t[z].ch[t[z].ch[1]==y] = x;
    Upd(y);
}
inline void pushdown(int y) {
    if(t[y].rev) {t[y].mt(); t[t[y].ch[0]].rev ^= 1; t[t[y].ch[1]].rev ^= 1; t[y].rev = 0;}
}
void Splay(int r, int tp) {
    for(int y, z; (y = t[r].f) != tp; rot(r)) {
        pushdown(r);
        z = t[y].f;
        if(z == tp) continue;
        if( (t[z].ch[0] == y) == (t[y].ch[0] == r) ) rot(y);
        else rot(r);
    }
    if(!tp) rt = r; Upd(r);
}
int Kth(int x)
{
    int y=rt,p;
    if(x>t[rt].sz)return 0;
    while(1)
    {
        pushdown(y);
        p=t[y].ch[0];
        if(t[p].sz+1<x) {
            x-=t[p].sz+1;
            y=t[y].ch[1];
        }
        else if(t[p].sz>=x) y=p;
        else return y;
    }
}
int Build(int l, int r) {
    if(l > r) return 0;
    int mid = (l + r) >> 1;
    t[mid].ch[0] = Build(l, mid-1);
    t[mid].ch[1] = Build(mid+1, r);
    Upd(mid); t[t[mid].ch[0]].f = t[t[mid].ch[1]].f = mid;
    return mid;
}
void Rev(int l, int r) {
    int a = Kth(l), b = Kth(r+2);
    Splay(a, 0); Splay(b, a); int p = t[b].ch[0];
    t[p].rev ^= 1;
}
void print(int x) {
    if(x == 0) return;
    pushdown(x);
    print(t[x].ch[0]);
    if(x != 1 && x != n + 2) printf("%d ", x-1);
    print(t[x].ch[1]);
}
char c, f;
inline void GET(int &n) {
    n = 0; f = 1;
    do {c = getchar(); if(c == '-') f = -1;} while(c > '9' || c < '0');
    while(c >= '0' && c <= '9') {n=n*10+c-'0';c=getchar();}
    n *= f;
}
int main() {
    int l, r;
    GET(n); GET(m);
    rt = Build(1, n+2);
    while(m --) {
        GET(l); GET(r);
        Rev(l, r);
    }
    print(rt);
}

指针版

/**************************************************************
    Problem: 3223
    User: geng4512
    Language: C++
    Result: Accepted
    Time:1912 ms
    Memory:5492 kb
****************************************************************/

#include<cstdio>
#define MAXN 200005
struct Node {
    int sz, v; bool rev; Node *ch[2], *fa;
    inline void sw() {Node *tmp = ch[0]; ch[0] = ch[1]; ch[1] = tmp; rev ^=1; }
}t[MAXN], NIL, *nil = &NIL, *rt;
int n, m;
inline void Upd(Node *p) {
    p->sz = p->ch[0]->sz + p->ch[1]->sz + 1;
}
inline void pushdown(Node *p) {
    if(p->rev) {
        p->rev = 0;
        if(p->ch[0] != nil) p->ch[0]->sw();
        if(p->ch[1] != nil) p->ch[1]->sw();
    }
}
Node *Build(int l, int r, Node*fa = nil) {
    if(l > r) return nil;
    int mid = (l + r) >> 1;
    t[mid].v = mid;
    t[mid].ch[0] = Build(l, mid-1, &t[mid]);
    t[mid].ch[1] = Build(mid+1, r, &t[mid]);
    t[mid].fa = fa; Upd(&t[mid]);
    return &t[mid];
}
void Rot(Node *x) {
    Node *y = x->fa, *z = y->fa;
    bool f = (y->ch[1] == x);
    pushdown(y); pushdown(x);
    y->ch[f] = x->ch[f^1];
    if(y->ch[f] != nil) y->ch[f]->fa = y;
    x->ch[f^1] = y; y->fa = x;
    x->fa = z;
    if(z != nil) z->ch[z->ch[1]==y] = x;
    Upd(y);
}
char c, f;
inline void GET(int &n) {
    n = 0; f = 1;
    do {c = getchar(); if(c == '-') f = -1;} while(c > '9' || c < '0');
    while(c >= '0' && c <= '9') {n=n*10+c-'0';c=getchar();}
    n *= f;
}
void Splay(Node *x, Node *to, Node *&Root = rt) {
    for(Node *y, *z; (y = x->fa) != to; Rot(x)) {
        z = y->fa;
        if(z == to) continue;
        if((z->ch[1] == y) == (y->ch[1] == x)) Rot(y);
        else Rot(x);
    } if(to == nil) Root = x;
    Upd(x);
}
Node *Kth(int k, Node *to = nil, Node *&Root = rt) {
    Node *y = Root, *z;
    if(y->sz < k) return nil;
    while(1) {
        pushdown(y);
        z = y->ch[0];
        if(z->sz + 1 < k) {
            k -= z->sz + 1;
            y = y->ch[1];
        } else if(z->sz >= k) y = y->ch[0];
        else break;
    }
    Splay(y, to, Root); return y;
}
inline void Rev(int l, int r) {
    Node *a = Kth(l), *b = Kth(r+2, a);
    b->ch[0]->sw();
}
void print(Node *p) {
    pushdown(p);
    if(p->ch[0] != nil) print(p->ch[0]);
    if(p->v != 1 && p->v != n+2) printf("%d ", p->v-1);
    if(p->ch[1] != nil) print(p->ch[1]);
}
int main() {
    //freopen("C:\\1.txt", "r", stdin);
    int l, r;
    GET(n); GET(m);
    rt = Build(1, n+2);
    while(m --) {
        GET(l); GET(r);
        Rev(l, r);
    }
    print(rt);
}
posted on 2015-11-22 16:43  geng4512  阅读(94)  评论(0编辑  收藏  举报