Splay(伸展树)/HDU6873
题目链接
http://acm.hdu.edu.cn/showproblem.php?pid=6873
题目大意
给定一组 \(n\) 列的方块,每列方块数 \(b_i\) ,现有 \(q\) 次操作/询问。
若 \(O = 1\) ,则将第 \(x\) 列第 \(y\) 个及其以上的方块向左推1格, \(x\) 列左侧部分方块也随之运动(如果存在,且能推动),并回答推动的方块总数目。
若 \(O = 2\) ,则回答第 \(x\) 列当前的方块数目。
注意:方块会受重力下落。
题目解析
使用 \(Splay\) 维护方块序列,时间复杂度:建树 \(O(n \log n)\) 、查询、删除和插入均为 \(O(\log n)\) ,因此总复杂度为 \(O((n+q) \log n)\) ,可以通过该题。
具体参见代码。
参考代码
#include
#define N 400005
#define EMPTY 0
#define INF INT_MAX
#define ll long long
using namespace std;
struct Tree{
int data, dataMin, dataMax, size, fa, child[2];
ll dataSum;
} t[N]; //其中data, fa, child为节点的基本属性
int cnt, root;
vector dataset, nodeBin;
inline void read(int &s) { //快读,支持int
s = 0;
int tt = 1, k = getchar();
for (; k < '0' || k > '9'; k = getchar()) if (k == '-') tt = -1;//判断该数正负
for (; k >= '0' && k <= '9'; k = getchar()) s = s * 10+(k ^ 48);//^48相当于-‘0’,较快。
s *= tt;
}
inline void write(ll s) { //快写,支持int和long long
int tt = 0, a[40];
if (s < 0) putchar('-'), s = -s;
do { a[++tt] = s % 10; } while (s /= 10);//用do while就不用特判一个0
while(tt) putchar(48+a[tt--]);
}
inline int checkSize(int x) { return (x == EMPTY) ? 0 : t[x].size;}
inline int checkDataMin(int x) { return (x == EMPTY) ? INF : t[x].dataMin;}
inline int checkDataMax(int x) { return (x == EMPTY) ? -INF : t[x].dataMax;}
inline ll checkDataSum(int x) { return (x == EMPTY) ? 0 : t[x].dataSum;}
inline void updNode(int x) {
t[x].size = checkSize(t[x].child[0]) + checkSize(t[x].child[1]) + 1;
t[x].dataMin = min(t[x].data, min(checkDataMin(t[x].child[0]), checkDataMin(t[x].child[1])));
t[x].dataMax = max(t[x].data, max(checkDataMax(t[x].child[0]), checkDataMax(t[x].child[1])));
t[x].dataSum = checkDataSum(t[x].child[0]) + checkDataSum(t[x].child[1]) + t[x].data;
}
void rotate(int x, int o)
{
int y = t[x].fa;
if (!y) return;
int z = t[y].fa;
t[y].child[o^1] = t[x].child[o];
if (t[x].child[o] != EMPTY) t[t[x].child[o]].fa = y;
t[x].fa = z;
if (z != EMPTY)
{
if (t[z].child[0] == y) t[z].child[0] = x;
else t[z].child[1] = x;
}
t[x].child[o] = y;
t[y].fa = x;
updNode(y);
updNode(x);
}
void splay(int x)
{
if (x == EMPTY) return;
int y;
while (t[x].fa != EMPTY)
{
y = t[x].fa;
if (t[y].fa == EMPTY) //旋转后为根节点
{
if (t[y].child[0] == x) rotate(x, 1);
else rotate(x, 0);
break;
}
else {
if (t[t[y].fa].child[1] == y)
{
if (t[y].child[0] == x) rotate(x, 1), rotate(x, 0);
else rotate(y, 0), rotate(x, 0);
}
else {
if (t[y].child[1] == x) rotate(x, 0), rotate(x, 1);
else rotate(y, 1), rotate(x, 1);
}
}
}
root = x;
}
inline int mininum(int x) { //找x的子树中序号最小的
while (t[x].child[0] != EMPTY) x = t[x].child[0];
return x;
}
inline int maxinum(int x) { //找x的子树中序号最大的
while (t[x].child[1] != EMPTY) x = t[x].child[1];
return x;
}
inline int succ(int x) { //找x的后继
splay(x);
if (t[x].child[1] == EMPTY) return EMPTY;
return mininum(t[x].child[1]);
}
inline int prec(int x) { //找x的前驱
splay(x);
if (t[x].child[0] == EMPTY) return EMPTY;
return maxinum(t[x].child[0]);
}
int createNode(int data) //新建节点,存放data(优先取用废弃内存池)
{
if (nodeBin.empty())
{
t[++cnt] = (Tree){data, data, data, 1, EMPTY, EMPTY, EMPTY, data};
return cnt;
}
int x = nodeBin.back();
t[x] = (Tree){data, data, data, 1, EMPTY, EMPTY, EMPTY, data};
nodeBin.pop_back();
return x;
}
int findKth(int x, int k) //找序号为k的节点
{
while (true)
{
if (x == EMPTY) return EMPTY;
int lc = checkSize(t[x].child[0]);
if (k <= lc) x = t[x].child[0];
else {
if (k == lc+1) return x;
else {x = t[x].child[1], k -= lc+1;}
}
}
}
inline int getKth(int x) { //找节点x的序号k
splay(x);
return checkSize(t[x].child[0]) + 1;
}
void insertKth(int x, int k) //将单节点x插入树中的序号k的位置
{
if (!root) {root = x; return;}
if (k <= 0 || k > t[root].size+1) return;
if (k == 1) {
int y = mininum(root);
if (y == EMPTY) return;
splay(y);
t[y].child[0] = x;
t[x].fa = y;
updNode(y);
return;
}
int y = findKth(root, k-1);
if (y == EMPTY) return;
splay(y);
t[x].child[1] = t[y].child[1];
if (t[y].child[1] != EMPTY) t[t[y].child[1]].fa = x;
t[y].child[1] = EMPTY;
t[x].child[0] = y;
t[y].fa= x;
root = x;
updNode(y);
updNode(x);
}
void deleteKth(int k) //删除树上序号为k的节点
{
if (!root) {return;}
if (k <= 0 || k > t[root].size) return;
if (k == 1) {
int y = mininum(root);
if (y == EMPTY) return;
nodeBin.push_back(y);
splay(y);
if (t[y].child[1] != EMPTY) t[t[y].child[1]].fa = EMPTY, root = t[y].child[1];
else root = 0;
return;
}
int y = findKth(root, k);
if (y == EMPTY) return;
splay(y);
nodeBin.push_back(y);
int z = prec(y);
t[z].child[1] = t[y].child[1];
if (t[y].child[1] != EMPTY) t[t[y].child[1]].fa = z;
t[t[y].child[0]].fa = EMPTY;
root = t[y].child[0];
while (z != EMPTY)
{
updNode(z);
z = t[z].fa;
}
}
int buildTree(int L, int R, int fa) //建树,data取用dataset[L]~[R],L>0
{
if (L > R) return EMPTY;
if (L == R) {
t[L] = (Tree){dataset[L], dataset[L], dataset[L], 1, fa, EMPTY, EMPTY, dataset[L]};
return L;
}
int mid = (L+R)/2;
t[mid] = (Tree){dataset[mid], 0, 0, 0, fa, EMPTY, EMPTY, 0};
t[mid].child[0] = buildTree(L, mid-1, mid);
t[mid].child[1] = buildTree(mid+1, R, mid);
updNode(mid);
return mid;
}
inline void clearAll() { //清空全部
cnt = 0;
dataset.clear();
nodeBin.clear();
root = 0;
}
int findData(int x, int data) //找到x的子树上<=Data的最大序号的节点
{
int a = EMPTY;
if (x == EMPTY) return EMPTY;
if (data < t[x].dataMin) return EMPTY;
if (t[x].child[1] != EMPTY) {
if (data >= checkDataMin(t[x].child[1])) {
a = findData(t[x].child[1], data);
}
}
if (a != EMPTY) return a;
if (t[x].data <= data) return x;
if (t[x].child[0] != EMPTY) {
if (data >= checkDataMin(t[x].child[0])) {
a = findData(t[x].child[0], data);
}
}
if (a != EMPTY) return a;
return EMPTY;
}
inline void printTree() { //将树上每个节点data按序输出
int x = mininum(root);
while (x != EMPTY) {
write(t[x].data);
x = succ(x);
if (x != EMPTY) putchar(' ');
}
putchar('\n');
}
int main()
{
int T, n, q;
read(T);
while (T--) {
clearAll();
read(n), read(q);
dataset.push_back(0);
for (int i = 0; i < n; ++i) {
int x;
read(x);
dataset.push_back(x);
}
root = buildTree(1, n, EMPTY);
while (q--)
{
int o, x, y, now;
read(o);
if (o == 1)
{
read(x), read(y);
now = findKth(root, x);
if (t[now].data < y) {putchar(48), putchar('\n'); continue;}
splay(now);
int p = findData(t[now].child[0], y-1);
if (p == EMPTY) {putchar(48), putchar('\n'); continue;}
ll tot = checkDataSum(t[now].child[0]) + t[now].data;
int r = succ(p);
if (r != EMPTY)
{
splay(r);
tot -= checkDataSum(t[r].child[0]);
t[r].data -= y-1 - t[p].data;
}
tot -= (ll)(getKth(now) - getKth(p))*(y-1);
deleteKth(getKth(p));
insertKth(createNode(y-1), x);
write(tot);
putchar('\n');
}
else {
read(x);
now = findKth(root, x);
if (now != EMPTY) write(t[now].data);
else putchar(48);
putchar('\n');
}
}
printTree();
}
return 0;
}
感谢支持!