Submission #739028

#	Time	Username	Problem	Language	Result	Execution time	Memory
739028		He_Huanglu	Maze (JOI23_ho_t3)	C++17	94 / 100	2090 ms	693192 KiB

Main

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
//#pragma GCC optimize("O3,fast-math,unroll-loops")
#include <bits/stdc++.h>
#define ii pair<int, int>
#define fi first
#define se second
using namespace std;

const int N = 6e6 + 1;
int n, m, s, rs, cs, re, ce;
int dx[4] = {0, -1, 0, 1};
int dy[4] = {-1, 0, 1, 0};
vector <int> f[N], a[N], p[2][N];
queue <ii> q[2];

void up(int u, int v, int val) {
    if(0 < u && u <= m && 0 < v && v <= n && !f[u][v]) {
        q[1].push({u, v});
        f[u][v] = val;
    }
}

int get(int t, int id, int u) {
    return p[t][id][u] == u ? u : p[t][id][u] = get(t, id, p[t][id][u]);
}

void upd(int t, int id, int i, int j, int val) {
    int u = get(t, id, i);
    while (u <= j) {
        if(t && !f[id][u]) {
            q[1].push({id, u});
            f[id][u] = val;
        }
        if(!t && !f[u][id]) {
            q[1].push({u, id});
            f[u][id] = val;
        }
        u = get(t, id, u + 1);
        p[t][id][i] = u;
    }
}

main () {
    cin.tie(0)->sync_with_stdio(0);
    if(fopen("task.inp", "r")) {
        freopen("task.inp", "r", stdin);
        freopen("wa.out", "w", stdout);
    }
    cin >> m >> n >> s >> rs >> cs >> re >> ce;
    for(int i = 1; i <= m; i++) a[i].resize(n + 1), f[i].resize(n + 1);
    for(int i = 1; i <= m; i++) {
        for(int j = 0; j <= n + 1; j++) p[1][i].push_back(j);
    }
    for(int i = 1; i <= n; i++) {
        for(int j = 0; j <= m + 1; j++) p[0][i].push_back(j);
    }
    for(int i = 1; i <= m; i++) {
        for(int j = 1; j <= n; j++) {
            char ch; cin >> ch;
            a[i][j] = (ch == '.' ? 1 : 0);
        }
    }
    q[1].push({rs, cs}); f[rs][cs] = 1;
    while (!q[1].empty() || !q[0].empty()) {
        while (!q[1].empty()) {
            int x, y; tie(x, y) = q[1].front(); q[1].pop();
            q[0].push({x, y});
            if(x == re && y == ce) return cout << f[x][y] - 1 << "\n", 0;
            for(int i = 0; i < 4; i++) {
                int u = x + dx[i], v = y + dy[i];
                if(0 < u && u <= m && 0 < v && v <= n && !f[u][v] && a[u][v]) {
                    f[u][v] = f[x][y];
                    q[1].push({u, v});
                }
            }
        }
        while (!q[0].empty()) {
            int x, y; tie(x, y) = q[0].front(); q[0].pop();
            if(x == rs && y == cs) {
                int s1 = max(1, x - s), s2 = max(1, y - s);
                int s3 = min(m, x + s), s4 = min(n, y + s);
                for(int i = s1; i <= s3; i++) {
                    for(int j = s2; j <= s4; j++) if(!f[i][j]) {
                        if(i == x - s && (j == y - s || j == y + s)) continue ;
                        if(i == x + s && (j == y - s || j == y + s)) continue ;
                        f[i][j] = f[x][y] + 1;
                        q[1].push({i, j});
                    }
                }
                continue ;
            }
            int val = f[x][y] + 1;
            for(int i = 0; i < 4; i++) {
                int u = x + dx[i], v = y + dy[i];
                up(x - s, y + s - 1, val);
                up(x + s, y + s - 1, val);
                if(y + s <= n) upd(0, y + s, max(1, x - s + 1), min(m, x + s - 1), val);
                up(x + s - 1, y - s, val);
                up(x + s - 1, y + s, val);
                if(x + s <= m) upd(1, x + s, max(1, y - s + 1), min(n, y + s - 1), val);
                up(x - s, y - s + 1, val);
                up(x + s, y - s + 1, val);
                if(y > s) upd(0, y - s, max(1, x - s + 1), min(m, x + s - 1), val);
                up(x - s + 1, y - s, val);
                up(x - s + 1, y + s, val);
                if(x > s) upd(1, x - s, max(1, y - s + 1), min(n, y + s - 1), val);
            }
        }
    }
}

Compilation message (stderr)

Main.cpp:44:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   44 | main () {
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:95:21: warning: unused variable 'u' [-Wunused-variable]
   95 |                 int u = x + dx[i], v = y + dy[i];
      |                     ^
Main.cpp:95:36: warning: unused variable 'v' [-Wunused-variable]
   95 |                 int u = x + dx[i], v = y + dy[i];
      |                                    ^
Main.cpp:47:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:48:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |         freopen("wa.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: 0 / 6