Submission #986094

#	Time	Username	Problem	Language	Result	Execution time	Memory
986094		VinhLuu	Maze (JOI23_ho_t3)	C++17	100 / 100	1025 ms	771420 KiB

Main

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
//#define int long long
//#define ll long long
#define fi first
#define se second
#define pb push_back
#define all(lmao) lmao.begin(), lmao.end()

using namespace std;

typedef pair<int,int> pii;
typedef tuple<int,int,int> tp;
const int N = 6e6 + 5;
const int oo = 1e9 + 1;
const int mod = 1e9 + 7;
//const ll oo = 5e18;

const int ha[4] = {1, -1, 0, 0};
const int co[4] = {0, 0, 1, -1};

int m, n, k, xt, yt, xs, ys;

int ans;

vector<int> f[N];
vector<int> a[N], ph[N], pc[N];
deque<tp> q;

bool kt(int x,int y){
    return x >= 1 && x <= m && y >= 1 && y <= n;
}

int row(int u,int v){
    return (ph[u][v] == v ? v : ph[u][v] = row(u, ph[u][v]));
}

int col(int u,int v){
    return (pc[u][v] == u ? u : pc[u][v] = col(pc[u][v], v));
}

void conduct(int val,int x,int y){
    int l = max(1, x - k + 1), r = min(m, x + k - 1), pl = max(1, y - k + 1), pr = min(n, y + k - 1);
    if(xt >= l && xt <= r && yt >= pl && yt <= pr) ans = min(ans, val + 1);
    if(l - 1 >= 1){
        int lx = l - 1, g = pr;
        while(ph[lx][g] >= pl){
            g = ph[lx][g];
            if(f[lx][g] > val + 1) f[lx][g] = val + 1, q.push_back({f[lx][g], lx, g});
            if(!ph[lx][g]) break;
            ph[lx][g] = ph[lx][g - 1];
            ph[lx][g] = row(lx, ph[lx][g]);
        }
    }
    if(r + 1 <= m){
        int lx = r + 1, g = pr;
        while(ph[lx][g] >= pl){
            g = ph[lx][g];
            if(f[lx][g] > val + 1) f[lx][g] = val + 1, q.push_back({f[lx][g], lx, g});
            if(!ph[lx][g]) break;
            ph[lx][g] = ph[lx][g - 1];
            ph[lx][g] = row(lx, ph[lx][g]);
        }
    }
    if(pl - 1 >= 1){
        int g = r, ly = pl - 1;
        while(pc[g][ly] >= l){
            g = pc[g][ly];
            if(f[g][ly] > val + 1) f[g][ly] = val + 1, q.push_back({f[g][ly], g, ly});
            if(!pc[g][ly]) break;
            pc[g][ly] = pc[g - 1][ly];
            pc[g][ly] = col(pc[g][ly], ly);
        }
    }

    if(pr + 1 <= n){
        int g = r, ly = pr + 1;
        while(pc[g][ly] >= l){
            g = pc[g][ly];
            if(f[g][ly] > val + 1) f[g][ly] = val + 1, q.push_back({f[g][ly], g, ly});
            if(!pc[g][ly]) break;
            pc[g][ly] = pc[g - 1][ly];
            pc[g][ly] = col(pc[g][ly], ly);
        }
    }
}

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

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

    cin >> m >> n >> k;
    cin >> xs >> ys >> xt >> yt;
    for(int i = 1; i <= m; i ++){
        string s; cin >> s;
        f[i].pb(oo);
        a[i].pb(0);
        ph[i].pb(0);
        pc[i].pb(0);
        for(int j = 0; j < n; j ++){
            f[i].pb(oo);
            pc[i].pb(0);
            ph[i].pb(j + 1);
            if(s[j] == '.') a[i].pb(0);
            else a[i].pb(1);
        }
        f[i].pb(oo);
        a[i].pb(0);
        ph[i].pb(0);
        pc[i].pb(0);
    }
    for(int i = 1; i <= n + 1; i ++) pc[0].pb(0);
    for(int i = 1; i <= n; i ++){
        for(int j = 1; j <= m; j ++){
            pc[j][i] = j;
        }
    }

    f[xs][ys] = 0;
    q.push_back({0, xs, ys});

    ans = oo;
    while(!q.empty()){
        int val, px, py; tie(val, px, py) = q.front();
        q.pop_front();
        if(val != f[px][py]) continue;
        if(px == xt && py == yt) ans = min(ans, val);

        conduct(val, px, py);

        for(int d = 0; d < 4; d ++){
            int x = px + ha[d];
            int y = py + co[d];
            if(!kt(x, y) || f[x][y] <= val || a[x][y]) continue;
            q.push_front({f[x][y] = val, x, y});
            if(ph[x][y]){
                ph[x][y] = ph[x][y - 1];
                ph[x][y] = row(x, ph[x][y]);
            }
            if(pc[x][y]){
                pc[x][y] = pc[x - 1][y];
                pc[x][y] = col(pc[x][y], y);
            }
        }
    }
    cout << min(ans, f[xt][yt]);
}

/*
6 6 3
5 4
2 1
###.#.
#..#..
...###
###.##
..#.##
#.#...
*/

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:94:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |         freopen(task ".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:95:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |         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