Submission #1253679

#	Time	Username	Problem	Language	Result	Execution time	Memory
1253679		nickolasarapidis	Obstacles for a Llama (IOI25_obstacles)	C++20	37 / 100	124 ms	66632 KiB

obstacles

#include "obstacles.h"
#include <bits/stdc++.h>
using namespace std;

const int MAXN = 200000;

int N, M;

vector<int> T(MAXN), H(MAXN), ST(4*MAXN);

int G[3][MAXN], id[3][MAXN];

int cnt = 0;

void dfs(int i, int j){
    if(id[i][j] != -1) return;
    id[i][j] = cnt;
    if(i + 1 < 3 and G[i + 1][j] == 0){
        dfs(i + 1, j);
    }
    if(i - 1 >= 0 and G[i - 1][j] == 0){
        dfs(i - 1, j);
    }
    if(j + 1 < M and G[i][j + 1] == 0){
        dfs(i, j + 1);
    }
    if(j - 1 >= 0 and G[i][j - 1] == 0){
        dfs(i, j - 1);
    }
}

void build(int v, int l, int r){
    if(l == r){
        ST[v] = H[l];
        return;
    }
    int m = (l + r)/2;
    build(2*v, l, m);
    build(2*v + 1, m + 1, r);
    ST[v] = max(ST[2*v], ST[2*v + 1]);
    return;
}

int query(int v, int l, int r, int a, int b){
    if(l > b or r < a) return 0;
    if(l >= a and r <= b) return ST[v];
    int m = (l + r)/2;
    return max(query(2*v, l, m, a, b), query(2*v + 1, m + 1, r, a, b));
}

bool can_reach(int l, int r, int s, int d){
    if(N == 3){
        return id[0][s] == id[0][d];
    }
    if(d < s) swap(s, d);
    if(query(1, 0, M - 1, s, d) >= T[N - 1]) return false;
    else return true;
}

void initialize(vector<int> A, vector<int> B){
    N = A.size(); M = B.size();
    for(int i = 0; i < N; i++){
        T[i] = A[i];
    }
    for(int i = 0; i < M; i++){
        H[i] = B[i];
    }
    build(1, 0, M - 1);
    if(N == 3){
        memset(id, -1, sizeof(id));
        for(int i = 0; i < M; i++){
            if(H[i] >= 2){
                G[0][i] = 1;
            }
            else G[0][i] = 0;
            
            if(H[i] >= 1){
                G[1][i] = 1;
            }
            else G[1][i] = 0;
            
            if(H[i] >= 3){
                G[2][i] = 1;
            }
            else G[2][i] = 0;
        }
        for(int i = 0; i < 3; i++){
            for(int j = 0; j < M; j++){
                if(id[i][j] != -1) continue;
                dfs(i, j);
                cnt++;
            }
        }
    }
}

• Subtask 0: 0 / 0
• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 13 / 13
• Subtask 4: 0 / 21
• Subtask 5: 0 / 25
• Subtask 6: 0 / 17