mirror of
https://gitcode.com/Zengtudor/alg2025.git
synced 2025-10-19 22:42:22 +00:00
94 lines
2.3 KiB
C++
94 lines
2.3 KiB
C++
#include <cstdint>
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#include <cstdio>
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#include <deque>
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#include <iostream>
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#include <istream>
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using ll = int64_t;
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#define sl static inline
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const ll maxn = 1005;
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ll n, m;
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int a[maxn][maxn];
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bool vis[maxn][maxn][4][2];
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int dir[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
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struct Q {
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Q(ll s, ll x, ll y, ll dir, bool is2) : s(s), x(x), y(y), dir(dir), is2(is2) {
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}
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ll s, x, y, dir;
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bool is2;
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};
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std::deque<Q> q;
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sl bool check(ll x, ll y, ll dir, bool is2) {
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if (x < 1 || x > n || y < 1 || y > m)
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return false;
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if (a[x][y] == 0)
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return false;
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if (a[x][y] == 3 && !is2)
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return false;
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return !vis[x][y][dir][is2];
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}
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int main() {
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std::iostream::sync_with_stdio(false);
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std::cin.tie(nullptr);
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std::cin >> n >> m;
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for (ll i = 1; i <= n; i++) {
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for (ll j = 1; j <= m; j++) {
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std::cin >> a[i][j];
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}
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}
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q.emplace_back(0, 1, 1, 0, false);
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vis[1][1][0][false] = true;
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while (q.size()) {
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auto [s, x, y, dd, is2] = q.front();
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q.pop_front();
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if (x == n && y == m) {
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std::cout << s << "\n";
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return 0;
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}
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if (a[x][y] == 4 && check(x+dir[dd][0], y+dir[dd][1], dd, is2)) {
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ll nx = x + dir[dd][0], ny = y + dir[dd][1];
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bool nis2 = (a[nx][ny] == 2);
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if (!check(nx, ny, dd, is2))
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continue;
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vis[nx][ny][dd][nis2] = true;
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q.emplace_back(s + 1, nx, ny, dd, nis2);
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continue;
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}
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for (ll i = 0; i < 4; i++) {
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ll nx = x + dir[i][0], ny = y + dir[i][1];
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if (nx < 1 || nx > n || ny < 1 || ny > m)
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continue;
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bool nis2 = is2;
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if (a[nx][ny] == 2)
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nis2 = true;
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if (a[nx][ny] == 4)
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nis2 = false;
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if(a[nx][ny]==4){
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if (!check(nx, ny, i, is2))
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continue;
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vis[nx][ny][i][nis2] = true;
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q.emplace_back(s + 1, nx, ny, i, nis2);
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}else{
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if(!check(nx, ny, 0, is2))
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continue;
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vis[nx][ny][0][nis2] = true;
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q.emplace_back(s + 1, nx, ny, 0, nis2);
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}
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}
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}
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std::cout << "-1\n";
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} |