POJ 3468 A Simple Problem with Integers (2)

POJ_3468 (2)

    第三次写这个题了，不过这次写的挺痛苦的，也是为了练基本的splay对区间的操作，不过写得比较挫……

    不过通过这次写splay的代码，感觉论文上rotate操作里面的push_down下传标记的操作是没有用的，因为调用rotate_to找对应节点的时候已经把标记都下传好了，而rotate操作也只是对rotate_to走过的路径上节点进行操作，因此该下传的就早已在调用rotate_to的时候下传完毕了。

#include<stdio.h>
#include<string.h>
#define MAXD 100010
int N, Q, T, node, left[MAXD], right[MAXD], size[MAXD], pre[MAXD], a[MAXD];
long long int key[MAXD], add[MAXD], sum[MAXD];
void update(int &T)
{
    sum[T] = sum[left[T]] + sum[right[T]] + key[T];
    size[T] = size[left[T]] + size[right[T]] + 1;
}
void push_down(int &T)
{
    key[T] += add[T];
    if(left[T])
    {
        add[left[T]] += add[T];
        sum[left[T]] += size[left[T]] * add[T];
    }
    if(right[T])
    {
        add[right[T]] += add[T];
        sum[right[T]] += size[right[T]] * add[T];
    }
    add[T] = 0;
}
void left_rotate(int x)
{
    int y = right[x], p = pre[x];
    right[x] = left[y];
    if(right[x])
        pre[right[x]] = x;
    left[y] = x;
    pre[x] = y;
    pre[y] = p;
    if(p != 0)
        right[p] == x ? right[p] = y : left[p] = y;
    else
        T = y;
    update(x);
}
void right_rotate(int x)
{
    int y = left[x], p = pre[x];
    left[x] = right[y];
    if(left[x])
        pre[left[x]] = x;
    right[y] = x;
    pre[x] = y;
    pre[y] = p;
    if(p != 0)
        right[p] == x ? right[p] = y : left[p] = y;
    else
        T = y;
    update(x);
}
void new_node(int &T, int v)
{
    T = ++ node;
    size[T] = 1;
    key[T] = v;
    add[T] = 0;
    left[T] = right[T] = 0;
}
void build(int &T, int x, int y, int fa)
{
    int mid = (x + y) / 2;
    new_node(T, a[mid]), pre[T] = fa;
    if(x < mid)
        build(left[T], x, mid - 1, T);
    if(mid < y)
        build(right[T], mid + 1, y, T);
    update(T);
}
void init()
{
    int i, j, k;
    for(i = 1; i <= N; i ++)
        scanf("%d", &a[i]);
    T = node = left[0] = right[0] = size[0] = key[0] = add[0] = sum[0] = 0;
    new_node(T, 0), new_node(right[T], 0);
    pre[T] = 0, pre[right[T]] = T;
    size[T] = 2;
    build(left[right[T]], 1, N, right[T]);
    update(right[T]), update(T);
}
void splay(int x, int goal)
{
    int y, z;
    for(;;)
    {
        if((y = pre[x]) == goal)
            break;
        if((z = pre[y]) == goal)
            right[y] == x ? left_rotate(y) : right_rotate(y);
        else
        {
            if(right[z] == y)
            {
                if(right[y] == x)
                    left_rotate(z), left_rotate(y);
                else
                    right_rotate(y), left_rotate(z);
            }
            else
            {
                if(left[y] == x)
                    right_rotate(z), right_rotate(y);
                else
                    left_rotate(y), right_rotate(z);
            }
        }
    }
    update(x);
}
void rotate_to(int k, int goal)
{
    int i = T, n;
    for(;;)
    {
        push_down(i);
        n = size[left[i]] + 1;
        if(k == n)
            break;
        if(k < n)
            i = left[i];
        else
        {
            k -= n;
            i = right[i];
        }
    }
    splay(i, goal);
}
void query(int x, int y)
{
    rotate_to(x, 0), rotate_to(y + 2, T);
    printf("%lld\n", sum[left[right[T]]]);
}
void refresh(int x, int y, int z)
{
    rotate_to(x, 0), rotate_to(y + 2, T);
    int k = left[right[T]];
    add[k] += z, sum[k] += z * size[k];
}
void solve()
{
    int i, j, k, x, y, z;
    char b[5];
    for(i = 0; i < Q; i ++)
    {
        scanf("%s", b);
        if(b[0] == 'Q')
        {
            scanf("%d%d", &x, &y);
            query(x, y);
        }
        else
        {
            scanf("%d%d%d", &x, &y, &z);
            refresh(x, y, z);
        }
    }
}
int main()
{
    while(scanf("%d%d", &N, &Q) == 2)
    {
        init();
        solve();
    }
    return 0;
}