poj3580 SuperMemo (splay)

思路：

其他的操作很简单，
要说的只有关于REVOLVE操作：
比如将区间[l, mid]接到区间[mid + 1, r]之后，可以先翻转区间[l, mid]，再翻转区间[mid + 1, r]，再翻转区间[l, r]。

代码：

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>

#define MAXN 100005
#define INF 0x3f3f3f3f

using namespace std;

int n, q;
int root, sz;
int arr[MAXN], id[MAXN];
int fa[MAXN], tr[MAXN][2];
int siz[MAXN];
int rev[MAXN], add[MAXN];
int mi[MAXN], v[MAXN];
int rec[MAXN];

void pushUp(int rt) {
    int l = tr[rt][0], r = tr[rt][1];
    siz[rt] = siz[l] + siz[r] + 1;
    mi[rt] = min(min(mi[l], mi[r]), v[rt]);
}

void pushDown(int rt) {
    int l = tr[rt][0], r = tr[rt][1];
    if (add[rt]) {
        v[rt] += add[rt];
        if (l) { add[l] += add[rt]; mi[l] += add[rt]; }
        if (r) { add[r] += add[rt]; mi[r] += add[rt]; }
        add[rt] = 0;
    }
    if (rev[rt]) {
        rev[rt] ^= 1;
        rev[l] ^= 1;
        rev[r] ^= 1;
        swap(tr[rt][0], tr[rt][1]);
    }
}

void build(int l, int r, int rt) {
    if (l > r) return;
    int now = id[l], last = id[rt];
    if (l == r) {
        v[now] = mi[now] = arr[l];
        fa[now] = last;
        siz[now] = 1;
        rev[now] = add[now] = 0;
        if (l < rt) tr[last][0] = now;
        else tr[last][1] = now;
        return;
    }
    int mid = l + r >> 1;
    now = id[mid];
    build(l, mid - 1, mid);
    build(mid + 1, r, mid);
    fa[now] = last;
    v[now] = arr[mid];
    pushUp(now);
    if (mid < rt) tr[last][0] = now;
    else tr[last][1] = now;
}

int find(int rt, int rank) {
    pushDown(rt);
    int l = tr[rt][0], r = tr[rt][1];
    if (siz[l] + 1 == rank) return rt;
    if (siz[l] + 1 > rank) return find(l, rank);
    return find(r, rank - siz[l] - 1);
}

void rotate(int x, int &k) {
    int y = fa[x], z = fa[y];
    int l, r;
    if (tr[y][0] == x) l = 0;
    else l = 1;
    r = l ^ 1;
    if (y == k) k = x;
    else {
        if (tr[z][0] == y) tr[z][0] = x;
        else tr[z][1] = x;
    }
    fa[x] = z;
    fa[y] = x;
    fa[tr[x][r]] = y;
    tr[y][l] = tr[x][r];
    tr[x][r] = y;
    pushUp(y);
    pushUp(x);
}

void splay(int x, int &k) {
    while (x != k) {
        int y = fa[x], z = fa[y];
        if (y != k) {
            if (tr[y][0] == x ^ tr[z][0] == y) rotate(x, k);
            else rotate(y, k);
        }
        rotate(x, k);
    }
}

void addUp(int a, int b) {
    int c;
    scanf("%d", &c);
    int x = find(root, a);
    int y = find(root, b + 2);
    splay(x, root);
    splay(y, tr[x][1]);
    int z = tr[y][0];
    add[z] += c;
    mi[z] += c;
    pushUp(y);
    pushUp(x);
}

void getMin(int a, int b) {
    int x = find(root, a);
    int y = find(root, b + 2);
    splay(x, root);
    splay(y, tr[x][1]);
    int z = tr[y][0];
    printf("%d\n", mi[z]);
    pushUp(y);
    pushUp(x);
}

void reverse(int a, int b) {
    int x = find(root, a);
    int y = find(root, b + 2);
    splay(x, root);
    splay(y, tr[root][1]);
    int z = tr[y][0];
    rev[z] ^= 1;
    pushUp(y);
    pushUp(x);
}

void revolve(int a, int b) {
    int k;
    scanf("%d", &k);
    int len = b - a + 1;
    k %= len;
    if (k < 0) k += len;
    if (k) {
        reverse(a, b - k);
        reverse(b - k + 1, b);
        reverse(a, b);
    }
}

void ins(int a, int b) {
    int k = a;
    arr[1] = b;
    if (rec[0]) id[1] = rec[rec[0]--];
    else id[1] = ++sz;
    build(1, 1, 0);
    int x = find(root, k + 1);
    int y = find(root, k + 2);
    int z = id[1];
    splay(x, root);
    splay(y, tr[root][1]);
    tr[y][0] = z;
    fa[z] = y;
    pushUp(y);
    pushUp(x);
}

void reclaim(int rt) {
    if (!rt) return;
    int l = tr[rt][0], r = tr[rt][1];
    reclaim(l);
    reclaim(r);
    fa[rt] = tr[rt][0] = tr[rt][1] = 0;
    add[rt] = rev[rt] = 0;
    rec[++rec[0]] = rt;
}

void del() {
    int k;
    scanf("%d", &k);
    int x = find(root, k);
    int y = find(root, k + 2);
    splay(x, root);
    splay(y, tr[root][1]);
    int z = tr[y][0];
    reclaim(z);
    tr[y][0] = 0;
    pushUp(y);
    pushUp(z);
}

int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++)
        scanf("%d", &arr[i + 1]);
    for (int i = 1; i <= n + 2; i++)
        id[i] = ++sz;
    mi[0] = INF;
    arr[1] = arr[n + 2] = INF;
    build(1, n + 2, 0);
    root = n + 3 >> 1;
    scanf("%d", &q);
    char op[8];
    int a, b;
    for (int i = 0; i < q; i++) {
        scanf("%s", op);
        if (op[0] == 'D') del();
        else {
            scanf("%d %d", &a, &b);
            if (op[0] == 'A') addUp(a, b);
            if (op[0] == 'M') getMin(a, b);
            if (op[0] == 'R')
                if (op[3] == 'E') reverse(a, b);
                else { revolve(a, b); }
            if (op[0] == 'I') ins(a, b);
        }
    }
    return 0;
}