Submission #241305

#TimeUsernameProblemLanguageResultExecution timeMemory
241305dolphingarlicRobots (APIO13_robots)C++14
100 / 100
924 ms126044 KiB
#include <bits/stdc++.h>
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("O3")
#pragma GCC target("sse4,avx2,fma,avx")
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;

const int INF = 250000;

int n, h, w;
char g[500][500];
pair<int, int> end_pos[500][500][4];
int dp[500][500][9][9];
vector<pair<int, int>> q[INF];

inline bool inside(int x, int y) {
	return (x >= 0 && y >= 0 && x < h && y < w && g[x][y] != 'x');
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> w >> h;
	memset(dp, 0x3f, sizeof(dp));

	FOR(i, 0, h) FOR(j, 0, w) {
		cin >> g[i][j];
		if (g[i][j] - '0' > 0 && g[i][j] - '0' < 10) {
			dp[i][j][g[i][j] - '1'][g[i][j] - '1'] = 0;
		}
		FOR(k, 0, 4) end_pos[i][j][k] = {-1, -1};
	}

	// Determine final positions from each push
	FOR(i, 0, h) FOR(j, 0, w) if (g[i][j] != 'x') {
		FOR(k, 0, 4) {
			pair<int, int> pos = {i, j};
			int d = (k + (g[i][j] == 'A') * 3 + (g[i][j] == 'C')) % 4;  // NESW

			while (true) {
				if (d == 0) {
					if (inside(pos.first - 1, pos.second)) pos.first--;
					else break;
				} else if (d == 1) {
					if (inside(pos.first, pos.second + 1)) pos.second++;
					else break;
				} else if (d == 2) {
					if (inside(pos.first + 1, pos.second)) pos.first++;
					else break;
				} else {
					if (inside(pos.first, pos.second - 1)) pos.second--;
					else break;
				}

				if (~end_pos[pos.first][pos.second][d].first) {
					pos = end_pos[pos.first][pos.second][d];
					break;
				}

				if (g[pos.first][pos.second] == 'A') d = (d + 3) % 4;
				if (g[pos.first][pos.second] == 'C') d = (d + 1) % 4;
			}

			end_pos[i][j][k] = pos;
		}
	}

	// Find the minimum no. of pushes to get robot k-l to block (i, j)
	FOR(rng, 0, n) {
		FOR(k, 0, n - rng) {
			int l = k + rng;
			FOR(i, 0, h) FOR(j, 0, w) if (g[i][j] != 'x') {
				FOR(d, k, l) {
					dp[i][j][k][l] =
						min(dp[i][j][k][l],
							dp[i][j][k][d] + dp[i][j][d + 1][l]);
				}
			}
		}

		FOR(k, 0, n - rng) {
			int l = k + rng;

			FOR(i, 0, h) FOR(j, 0, w) if (g[i][j] != 'x') {
				if (dp[i][j][k][l] <= INF) q[dp[i][j][k][l]].push_back({i, j});
			}
			
			FOR(i, 0, INF) {
				for (pair<int, int> pos : q[i]) {
					int x, y;
					tie(x, y) = pos;
					if (dp[x][y][k][l] == i) {
						FOR(d, 0, 4) {
							int nx, ny;
							tie(nx, ny) = end_pos[x][y][d];
							if (dp[nx][ny][k][l] > dp[x][y][k][l] + 1) {
								q[dp[nx][ny][k][l] = dp[x][y][k][l] + 1].push_back({nx, ny});
							}
						}
					}
				}
				q[i].clear();
			}
		}
	}

	int ans = INT_MAX;
	FOR(i, 0, h) FOR(j, 0, w) ans = min(ans, dp[i][j][0][n - 1]);
	cout << (ans > INF ? -1 : ans);
	return 0;
}

Compilation message (stderr)

robots.cpp: In function 'int main()':
robots.cpp:77:42: warning: array subscript is above array bounds [-Warray-bounds]
        dp[i][j][k][d] + dp[i][j][d + 1][l]);
                         ~~~~~~~~~~~~~~~~~^
robots.cpp:77:39: warning: array subscript is above array bounds [-Warray-bounds]
        dp[i][j][k][d] + dp[i][j][d + 1][l]);
                         ~~~~~~~~~~~~~~^
robots.cpp:75:19: warning: array subscript is above array bounds [-Warray-bounds]
      dp[i][j][k][l] =
      ~~~~~~~~~~~~~^
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