Submission #46921

#	Time	Username	Problem	Language	Result	Execution time	Memory
46921		minkank	Robots (APIO13_robots)	C++17	100 / 100	603 ms	105540 KiB

robots

#include <bits/stdc++.h>
 
#define fi first
#define se second
 
using namespace std;
 
const int N = 505;
const int M = 10;
const int INF = 0x3f3f3f3f;
 
const int dr[] = {-1, 0, 1, 0};
const int dc[] = {0, 1, 0, -1};
 
struct State {
	pair<int, int> p;
	int x, y;
 
	State() {}
 
	State (pair<int, int> p, int x, int y) :
		p(p), x(x), y(y) {}
};
 
int n, h, w;
int dis[M][M][N][N];
State nxt[N][N][4][2];
bool visit[N][N][4][2];
char a[N][N];
vector< pair<int, int> > vec[N * N];
 
// A -1
// C +1
 
State dfs(int r, int c, int x, int y) {
	if (visit[r][c][x][y]) return nxt[r][c][x][y];
	visit[r][c][x][y] = 1;
	if (y == 0 && (a[r][c] == 'A' || a[r][c] == 'C')) {
		int nx = x;
		if (a[r][c] == 'A') {
			nx--; if (nx == -1) nx = 3;
		}
		else {
			nx++; if (nx == 4) nx = 0;
		}
		return nxt[r][c][x][y] = dfs(r, c, nx, 1);
	}
	else {
		int nr, nc;
		nr = r + dr[x], nc = c + dc[x];
		if (nr < 1 || nc < 1 || nr > h || nc > w || a[nr][nc] == 'x') {
			return nxt[r][c][x][y] = State({r, c}, x, y);
		}
		else {
			return nxt[r][c][x][y] = dfs(nr, nc, x, 0);
		}
	}
}
 
void bfs(int l, int r) {
	queue< pair<int, int> > qu;

	for (int i = 0; i <= w * h; ++i) {
		while (vec[i].size()) qu.push(vec[i].back()), vec[i].pop_back();

		int sz = qu.size();

		while (sz--) {
			pair<int, int> u = qu.front(); qu.pop();
			if (dis[l][r][u.fi][u.se] != i) continue;
			for (int j = 0; j < 4; ++j) {
				pair<int, int> v = nxt[u.fi][u.se][j][1].p;
				if (dis[l][r][v.fi][v.se] > i + 1) {
					dis[l][r][v.fi][v.se] = i + 1, qu.push(v);
				}
			}
		}
	}
}
 
void go(int l, int r) {
	for (int i = 1; i <= h; ++i) {
		for (int j = 1; j <= w; ++j) {
			if (dis[l][r][i][j] <= w * h) {
				vec[dis[l][r][i][j]].push_back({i, j});
			}
		}
	}
	bfs(l, r);
}
 
int main() {
	cin >> n >> w >> h; getchar();
 
	for (int l = 1; l <= n; ++l) {
		for (int r = l; r <= n; ++r) {
			for (int i = 1; i <= h; ++i) {
				for (int j = 1; j <= w; ++j) {
					dis[l][r][i][j] = INF;
				}
			}
		}
	}
	
	for (int i = 1; i <= h; ++i) {
		for (int j = 1; j <= w; ++j) {
			a[i][j] = getchar();
			if (a[i][j] >= '1' && a[i][j] <= '9') {
				int x = a[i][j] - '0';
				dis[x][x][i][j] = 0;
			}
		}		
		getchar();
	}
 
	for (int i = 1; i <= h; ++i) {
		for (int j = 1; j <= w; ++j) {
			for (int k = 0; k < 4; ++k) {
				dfs(i, j, k, 1);
				// cout << "#nxt " << i << ' ' << j << ' ' << k << ":\n";
				// cout << nxt[i][j][k][1].p.fi << ' ' << nxt[i][j][k][1].p.se << '\n';
			}
		}
	}
 
	for (int i = 1; i <= n; ++i) go(i, i);
 
	for (int i = 2; i <= n; ++i) {
		for (int l = 1; l + i - 1 <= n; ++l) {
			int r = l + i - 1;
			for (int m = l; m < r; ++m) {
				for (int j = 1; j <= h; ++j) {
					for (int k = 1; k <= w; ++k) {
						dis[l][r][j][k] = min(dis[l][r][j][k], dis[l][m][j][k] + dis[m + 1][r][j][k]);
					}
				}
			}
			go(l, r);
		}
	}
 
	// for (int l = 1; l <= n; ++l) {
	// 	for (int r = l; r <= n; ++r) {
	// 		cout << "#at " << l << ' ' << r << '\n';
	// 		for (int i = 1; i <= h; ++i) {
	// 			for (int j = 1; j <= w; ++j) {
	// 				cout << dis[l][r][i][j] << ' ';
	// 			}
	// 			cout << '\n';
	// 		}
	// 	}
	// }
 
	int res = INF;
	for (int i = 1; i <= h; ++i) {
		for (int j = 1; j <= w; ++j) {
			res = min(res, dis[1][n][i][j]);
		}
	}
	if (res == INF) cout << -1; else cout << res;
 
	// cerr << '\n' << clock() * 1000 / CLOCKS_PER_SEC;
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 40 / 40