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OI-codes/Luogu/P3224/P3224.cpp

229 lines
4.5 KiB
C++

#include <iostream>
#include <cstdlib>
#include <limits>
#include <numeric>
using std::cin;
using std::cout;
const char endl = '\n';
const int N = 1e5 + 5;
class Treap {
private:
struct node {
node *left, *right;
int size, val, key;
node(const int &_val = 0)
: left(nullptr), right(nullptr), size(1), val(_val), key(rand()) {}
~node() {
delete left;
delete right;
}
void pushup() {
size = 1;
if (left != nullptr) size += left->size;
if (right != nullptr) size += right->size;
}
} * root;
inline int getNodeSize(node *node) {
return node == nullptr ? 0 : node->size;
}
node *find(node *p, int val) {
if (p == nullptr) return nullptr;
if (p->val == val) return p;
if (p->val > val) return find(p->left, val);
return find(p->right, val);
}
std::pair<node *, node *> split(node *p, int k) {
if (p == nullptr) return std::make_pair(nullptr, nullptr);
std::pair<node *, node *> o;
if (k <= getNodeSize(p->left)) {
o = split(p->left, k);
p->left = o.second;
p->pushup();
o.second = p;
} else {
o = split(p->right, k - getNodeSize(p->left) - 1);
p->right = o.first;
p->pushup();
o.first = p;
}
return o;
}
std::pair<node *, node *> splitByValue(node *p, int val) {
if (p == nullptr) return std::make_pair(nullptr, nullptr);
std::pair<node *, node *> o;
if (p->val < val) {
o = splitByValue(p->right, val);
p->right = o.first;
p->pushup();
o.first = p;
} else {
o = splitByValue(p->left, val);
p->left = o.second;
p->pushup();
o.second = p;
}
return o;
}
node *merge(node *x, node *y) {
if (x == nullptr) return y;
if (y == nullptr) return x;
if (x->key > y->key) {
x->right = merge(x->right, y);
x->pushup();
return x;
}
y->left = merge(x, y->left);
y->pushup();
return y;
}
void _merge(node *cur) {
if (cur->left != nullptr) _merge(cur->left);
if (cur->right != nullptr) _merge(cur->right);
insert(cur->val);
}
public:
Treap()
: root(nullptr) {}
~Treap() {
delete root;
}
void insert(int val) {
auto o = splitByValue(root, val);
o.first = merge(o.first, new Treap::node(val));
root = merge(o.first, o.second);
}
void erase(int val) {
auto o = splitByValue(root, val);
auto t = o;
if (find(o.second, val) != nullptr) {
t = split(o.second, 1);
delete t.first;
}
root = merge(o.first, t.second);
}
int getRank(int val) {
auto x = splitByValue(root, val);
int r = getNodeSize(x.first) + 1;
root = merge(x.first, x.second);
return r;
}
int getKth(int k) {
auto x = split(root, k - 1);
auto y = split(x.second, 1);
Treap::node *o = y.first;
root = merge(x.first, merge(y.first, y.second));
return o == nullptr ? 0 : o->val;
}
int size() {
return getNodeSize(root);
}
void merge(Treap &b) {
_merge(b.root);
}
} tr[N];
int n, m, q, a[N], fa[N];
int find(int x) {
return fa[x] == x ? x : fa[x] = find(fa[x]);
}
void merge(int x, int y) {
x = find(x);
y = find(y);
if (x != y) {
if (tr[x].size() < tr[y].size()) {
fa[x] = y;
tr[y].merge(tr[x]);
} else {
fa[y] = x;
tr[x].merge(tr[y]);
}
}
}
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m;
a[0] = -1;
for (int i = 1, x; i <= n; i++) {
cin >> x;
a[x] = i;
fa[i] = i;
tr[i].insert(x);
}
for (int i = 1, u, v; i <= m; i++) {
cin >> u >> v;
merge(u, v);
}
cin >> q;
while (q--) {
char op;
int x, y;
cin >> op >> x >> y;
if (op == 'Q') {
auto &t = tr[find(x)];
if (t.size() < y) {
cout << -1 << endl;
} else {
cout << a[t.getKth(y)] << endl;
}
} else { // op == 'B'
merge(x, y);
}
}
return 0;
}