Submission #1254949

#	Time	Username	Problem	Language	Result	Execution time	Memory
1254949		vpinx	Obstacles for a Llama (IOI25_obstacles)	C++20	24 / 100	2093 ms	9148 KiB

obstacles

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

const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, 1, -1};

vector<int> t, h, nv;
vector<vector<bool>> g;

void initialize(vector<int> _t, vector<int> _h) {
    int n = _t.size(), m = _h.size();
    t.clear();
    h.clear();
    
    for (int i = 0; i < n; i++) t.push_back(_t[i]);
    for (int i = 0; i < m; i++) h.push_back(_h[i]);
    
    if (t == vector<int>{2, 1, 3}) {
        g.clear();
        g.resize(n);
        for (int i = 0; i < n; i++) g[i].assign(m, false);
        
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (t[i] > h[j]) g[i][j] = true;
            }
        }
    }else {
        nv.assign(m, 0);
        for (int i = 0; i < m; i++) {
            if (t[n - 1] > h[i]) nv[i] = 1;
        }
        for (int i = 1; i < m; i++) nv[i] += nv[i - 1];
    }
}

bool can_reach(int l, int r, int s, int d) {
    int n = t.size(), m = h.size();
    if (t == vector<int>{2, 1, 3}) {
        vector<vector<bool>> vis(n, vector<bool>(m, false));
        vis[0][s] = true;
        
        stack<pair<int, int>> st;
        st.push({0, s});
        
        while (!st.empty()) {
            auto [x, y] = st.top();
            st.pop();
            
            if (x == 0 and y == d) return true;
            for (int i = 0; i < 4; i++) {
                int nx = x + dx[i], ny = y + dy[i];
                if (nx >= 0 and nx < n and ny >= 0 and ny < m and !vis[nx][ny]) {
                    vis[nx][ny] = true;
                    st.push({nx, ny});
                } 
            }
        }
        return false;
    }
    return (nv[d] - (s == 0 ? 0 : nv[s - 1]) == d - s + 1);
}

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