#include <bits/stdc++.h>
using namespace std;
mt19937 rng(time(0));
struct Node {
char val;
int prior;
int sz;
Node *left;
Node *right;
Node(char c) {
val = c;
prior = rng();
sz = 1;
left = nullptr;
right = nullptr;
}
} *root;
int get_sz(Node *nd) { return nd == nullptr ? 0 : nd->sz; }
void upd(Node *&nd) { nd->sz = get_sz(nd->left) + get_sz(nd->right) + 1; }
void Merge(Node *&treap, Node *left, Node *right) {
if (left == nullptr) { treap = right; return; }
if (right == nullptr) { treap = left; return; }
if (left->prior > right->prior) {
Merge(left->right, left->right, right);
treap = left;
} else {
Merge(right->left, left, right->left);
treap = right;
}
upd(treap);
}
void Split(Node *treap, Node *&left, Node *&right, int val) {
if (treap == nullptr) {
left = nullptr;
right = nullptr;
return;
}
if (get_sz(treap->left) < val) {
Split(treap->right, treap->right, right, val - get_sz(treap->left) - 1);
left = treap;
} else {
Split(treap->left, left, treap->left, val);
right = treap;
}
upd(treap);
}
void dfs(Node *nd) {
if (nd == nullptr) return;
dfs(nd->left);
printf("%c", nd->val);
dfs(nd->right);
}
const int N = 1e6 + 10;
int n, q;
string s;
char Query(int idx) {
Node *a, *b;
Split(root, a, b, idx - 1);
Node *c, *d;
Split(b, c, d, 1);
char res = c->val;
Merge(b, c, d);
Merge(root, a, b);
return res;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(nullptr);
cin >> n >> q;
cin >> s;
for (int i = 0; i < n; i++) {
Merge(root, root, new Node(s[i]));
}
while (q--) {
char c;
cin >> c;
if (c == 'a') {
int i, j;
cin >> i >> j;
if (i < j) j--;
Node *a, *b;
Split(root, a, b, i - 1);
Node *c, *d;
Split(b, c, d, 1);
Merge(root, a, d);
Split(root, a, b, j - 1);
Merge(d, a, c);
Merge(root, d, b);
} else {
int i;
cin >> i;
cout << Query(i) << '\n';
}
}
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
