Submission #1185038

#	Time	Username	Problem	Language	Result	Execution time	Memory
1185038		starnightsnow	Crayfish scrivener (IOI12_scrivener)	C++20	100 / 100	519 ms	93136 KiB

scrivener

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int MAXN = 2000005;
const int LOG = 20;

vector<char> v;      
vector<int> parent;      
vector<int> sz;      
vector<int> mp;   
vector<vector<int>> up; 

int cur = 0;

void Init() {
    v.assign(1, 0);    
    parent.assign(1, -1);  
    sz.assign(1, 0);   
    mp.assign(1, 0);
    up.assign(1, vector<int>(LOG, -1));
    cur = 0;
}

void TypeLetter(char L) {
    int new_version = v.size();
    v.push_back(L);
    parent.push_back(cur);
    sz.push_back(sz[cur] + 1);
    
    up.push_back(vector<int>(LOG, -1));
    up[new_version][0] = parent[new_version];
    
    for (int j = 1; j < LOG; ++j) 
        if (up[new_version][j-1] != -1) 
            up[new_version][j] = up[up[new_version][j-1]][j-1];

    mp.push_back(new_version);
    cur = new_version;
}

void UndoCommands(int U) {
    int undo = mp[mp.size() - 1 - U];
    mp.push_back(undo);
    cur = undo;
}

char GetLetter(int P) {
    int now = cur;
    int need = sz[now] - 1 - P;
    for (int j = LOG - 1; j >= 0; --j) {
        if (need >= (1 << j) && now != -1) {
            now = up[now][j];
            need -= (1 << j);
        }
    }
    return v[now];
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 22 / 22
• Subtask 4: 26 / 26
• Subtask 5: 40 / 40