Submission #754582

#	Time	Username	Problem	Language	Result	Execution time	Memory
754582		MilosMilutinovic	Collider (IZhO11_collider)	C++14	100 / 100	171 ms	49400 KiB

collider

#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);
    cout << 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) {
                continue;
            }
            if (i < j) {
                Node *pre_i, *od_i;
                Split(root, pre_i, od_i, i - 1);
                Node *na_i, *posle_i;
                Split(od_i, na_i, posle_i, 1);
                Node *do_j, *posle_j;
                Split(posle_i, do_j, posle_j, j - i);
                Node *a, *b;
                Merge(a, pre_i, do_j);
                Merge(b, a, na_i);
                Merge(root, b, posle_j);
            } else {
                Node *pre_j, *od_j;
                Split(root, pre_j, od_j, j - 1);
                Node *pre_i, *od_i;
                Split(od_j, pre_i, od_i, i - j);
                Node *na_i, *posle_i;
                Split(od_i, na_i, posle_i, 1);
                Node *a, *b;
                Merge(a, pre_j, na_i);
                Merge(b, a, pre_i);
                Merge(root, b, posle_i);
            }
        } else {
            int i;
            cin >> i;
            cout << Query(i) << '\n';
        }
    }
}

• Subtask 1: 100 / 100