_bzoj3224 Tyvj 1728 普通平衡树【Splay】

传送门：http://www.lydsy.com/JudgeOnline/problem.php?id=3224

保存splay模版

一刻不停写了一个小时多一点，幸好一遍过了！（其实带着freopen wa了一次）

添加一个易出bug的地方叭（鉴于曾经有次这么错过）：此题平衡树里可以用重复值，我是用tm保存出现的次数，因此在求第k大时，千万小心循环结束条件！

#include <cstdio>
#include <algorithm>

const int maxn = 200005;

int fa[maxn], ch[maxn][2], key[maxn], tm[maxn], siz[maxn], root, cnt, t1, t2;

inline void pushup(int x) {
siz[x] = siz[ch[x][0]] + siz[ch[x][1]] + tm[x];
}
inline void rotate(int x) {
int y = fa[x];
if (y == ch[fa[y]][0]) {
ch[fa[y]][0] = x;
}
else {
ch[fa[y]][1] = x;
}
fa[x] = fa[y];
int dir = x == ch[y][1];
ch[y][dir] = ch[x][dir ^ 1];
fa[ch[x][dir ^ 1]] = y;
ch[x][dir ^ 1] = y;
fa[y] = x;
pushup(y);
pushup(x);
}
inline void splay(int x) {
int p, flag1, flag2;
while (fa[x]) {
p = fa[x];
if (!fa
) {
rotate(x);
}
else {
flag1 = x == ch[p][1];
flag2 = p == ch[fa[p]][1];
if (flag1 ^ flag2) {
rotate(x);
}
else {
rotate(p);
}
rotate(x);
}
}
root = x;
}
bool ist(int x, int val, int p, int dir) {
if (!x) {
key[++cnt] = val;
tm[cnt] = 1;
siz[cnt] = 1;
fa[cnt] = p;
ch[p][dir] = cnt;
return true;
}
if (val < key[x]) {
bool rt = ist(ch[x][0], val, x, 0);
pushup(x);
return rt;
}
else if (val > key[x]) {
bool rt = ist(ch[x][1], val, x, 1);
pushup(x);
return rt;
}
else {
++tm[x];
++siz[x];
return false;
}
}
inline int fndmin(int x) {
int rt = x, mn = key[x];
for (int i = ch[x][0]; i; i = ch[i][0]) {
if (mn > key[i]) {
mn = key[rt = i];
}
}
return rt;
}
inline int fndmax(int x) {
int rt = x, mx = key[x];
for (int i = ch[x][1]; i; i = ch[i][1]) {
if (mx < key[i]) {
mx = key[rt = i];
}
}
return rt;
}
void del(int x, int value) {
if (!x) {
return;
}
if (value < key[x]) {
del(ch[x][0], value);
pushup(x);
}
else if (value > key[x]) {
del(ch[x][1], value);
pushup(x);
}
else if (tm[x] > 1) {
--tm[x];
--siz[x];
}
else {
splay(x);
fa[ch[x][0]] = fa[ch[x][1]] = 0;
if (!ch[x][0]) {
root = ch[x][1];
}
else if (!ch[x][1]) {
root = ch[x][0];
}
else {
root = fndmax(ch[x][0]);
splay(root);
fa[ch[x][1]] = root;
ch[root][1] = ch[x][1];
pushup(root);
}
}
}
inline int qianqu(int val) {
if (ist(root, val, 0, 0)) {
splay(cnt);
}
int x = root;
while (val != key[x]) {
x = ch[x][val > key[x]];
}
splay(x);
x = key[fndmax(ch[x][0])];
del(root, val);
return x;
}
inline int houji(int val) {
if (ist(root, val, 0, 0)) {
splay(cnt);
}
int x = root;
while (val != key[x]) {
x = ch[x][val > key[x]];
}
splay(x);
x = key[fndmin(ch[x][1])];
del(root, val);
return x;
}
inline int getrank(int val) {
int x = root;
while (key[x] != val) {
x = ch[x][val > key[x]];
}
splay(x);
return siz[ch[x][0]] + 1;
}
inline int getnum(int rank) {
int x = root;
while (rank <= siz[ch[x][0]] || rank > siz[ch[x][0]] + tm[x]) {
if (rank <= siz[ch[x][0]]) {
x = ch[x][0];
}
else {
rank -= siz[ch[x][0]] + tm[x];
x = ch[x][1];
}
}
return key[x];
}

int main(void) {
int n;
scanf("%d", &n);
while (n--) {
scanf("%d%d", &t1, &t2);
if (t1 == 1) {
if (ist(root, t2, 0, 0)) {
splay(cnt);
}
}
else if (t1 == 2) {
del(root, t2);
}
else if (t1 == 3) {
printf("%d\n", getrank(t2));
}
else if (t1 == 4) {
printf("%d\n", getnum(t2));
}
else if (t1 == 5) {
printf("%d\n", qianqu(t2));
}
else {
printf("%d\n", houji(t2));
}
}
return 0;
}