Submission #1281729

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281729		tunademayo	Maze (JOI23_ho_t3)	C++20	100 / 100	981 ms	239228 KiB

Main

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

#define ll long long
#define _y1 y1

const bool Multitest = 0;

const int N = 6e6 + 10;

int n, m, r;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {1, 0, -1, 0};
int a[N], d[N], dp[N];
int f[N];

int d2[N];

bitset<N> vis;

struct Data
{
    int x, y, val;

    Data() { }

    Data(int _x, int _y, int _val) : x(_x), y(_y), val(_val) { }
};  deque<Data> q;

int id(int i, int j)
{
    return (i - 1) * m + j;
}

int find(int i, int u)
{
    if(d[id(i, u)] == u) return u;

    int v = find(i, d[id(i, u)]);

    d[id(i, u)] = v;

    return v;
}

void merge(int i, int u, int v)
{
    u = find(i, u), v = find(i, v);

    d[id(i, u)] = v;
}

int find2(int i, int u)
{
    if(d2[id(i, u)] == i) return i;

    int v = find2(d2[id(i, u)], u);

    d2[id(i, u)] = v;

    return v;
}

void merge2(int u, int v, int i)
{
    u = find2(u, i), v = find2(v, i);

    d2[id(u, i)] = v;
}

void update(int i, int j, int l, int r, int val)
{
    if(i == j)
    {
        if(i <= 0 || i > n) return;
    }

    i = max(1, i);
    j = min(j, n);

    l = max(1, l);
    r = min(r, m);

    //cerr << i << ' ' << j << ' ' << l << ' ' << r << '\n';

    int I = find2(i, l);

    while(I <= j)
    {
        //cerr << I << ' ' << l << ' ' << r << '\n';
        int fi = find(I, l);

        while(fi <= r)
        {
            if(dp[id(I, fi)] == -1)
            {
                q.push_back(Data(I, fi, val));
            }

            if(fi == m) break;

            merge(I, fi, fi + 1);
            fi = find(I, fi);
        }

        if(I == n) return;

        if(i != j)
        {
            merge2(I, I + 1, l);
            I = find2(I, l);
        }
        else return;
    }
}

void work()
{
    cin >> n >> m >> r;

    int x1, x2, y1, y2; cin >> x1 >> y1 >> x2 >> y2;

    for(int i = 1 ; i <= n ; i++)
    {
        for(int j = 1 ; j <= m ; j++)
        {
            d[id(i, j)] = j;
            d2[id(i, j)] = i;
        }
    }

    for(int i = 1 ; i <= n ; i++)
    {
        for(int j = 1 ; j <= m ; j++)
        {
            char c; cin >> c;

            if(c == '.') a[id(i, j)] = 1;
        }
    }

    q.push_back(Data(x1, y1, 0));

    vis[id(x1, y1)] = 1;
    memset(dp, -1, sizeof dp);
    while(!q.empty())
    {
        Data u = q.front(); q.pop_front();

        if(u.y != m) merge(u.x, u.y, u.y + 1);

        if(dp[id(u.x, u.y)] != -1) continue;

        dp[id(u.x, u.y)] = u.val;

        // bfs -> 0

        for(int i = 0 ; i < 4 ; i++)
        {

            int x = u.x + dx[i];
            int y = u.y + dy[i];

            if(1 <= x && x <= n)
            {
                if(1 <= y && y <= m)
                {
                    if(vis[id(x, y)] == 1) continue;
                    if(a[id(x, y)] == 0) continue;

                    q.push_front(Data(x, y, u.val));

                    vis[id(x, y)] = 1;
                }
            }
        }

        // bfs 1
        int x = u.x, y = u.y;

        update(x - r, x - r, y - r + 1, y + r - 1, u.val + 1); //cerr << "Done b1";
        update(x - r + 1, x + r -1 , y - r, y + r, u.val + 1); //cerr << "Done b2";
        update(x + r, x + r, y - r + 1, y + r - 1, u.val + 1); //cerr << "Done b3";
    }
    cout << dp[id(x2, y2)];
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    int q = 1;

    if(fopen("task.inp", "r"))
    {
        freopen("task.inp", "r", stdin);
        freopen("task.out", "w", stdout);
    }

    if(Multitest)   cin >> q;

    while(q--) work();
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:197:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  197 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:198:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  198 |         freopen("task.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 19 / 19
• Subtask 3: 16 / 16
• Subtask 4: 19 / 19
• Subtask 5: 5 / 5
• Subtask 6: 19 / 19
• Subtask 7: 8 / 8
• Subtask 8: 6 / 6