Submission #46755

#	Time	Username	Problem	Language	Result	Execution time	Memory
46755		Bruteforceman	Portals (BOI14_portals)	C++11	100 / 100	340 ms	57764 KiB

portals

#include "bits/stdc++.h"
using namespace std;
char s[1004][1004];
int d[1004][1004];
int dis[1004][1004];

const int dx[] = {0, 0, 1, -1};
const int dy[] = {1, -1, 0, 0};

typedef pair <int, int> pii;
const int inf = 1e9;
pii cell[4][1004][1004];
int n, m;

bool inside(int x, int y) {
	return (0 <= x && x < n) && (0 <= y && y < m);
}

struct node {
	int x, y;
	int dist;
	node () {}
	node (int x, int y, int dist) : x(x), y(y), dist(dist) {}
	bool operator < (node p) const {
		return dist > p.dist;
	}
};

int main(int argc, char const *argv[])
{
	scanf("%d %d", &n, &m);
	for(int i = 0; i < n; i++) {
		scanf("%s", s[i]);
	}
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			d[i][j] = inf;
		}
	}
	queue <pii> Q; 
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			if(s[i][j] == '#') continue;
			bool good = false;
			for(int x = 0; x < 4; x++) {
				int p = i + dx[x];
				int q = j + dy[x];
				if(!inside(p, q) || s[p][q] == '#') {
					good = true;
					break;
				}
			}
			if(good) {
				Q.push(pii(i, j));
				d[i][j] = 0;
			}
		}
	}
	while(!Q.empty()) {
		int x = Q.front().first;
		int y = Q.front().second;
		Q.pop();
		for(int i = 0; i < 4; i++) {
			int p = x + dx[i];
			int q = y + dy[i];
			if(d[p][q] > d[x][y] + 1 && s[p][q] != '#') {
				d[p][q] = d[x][y] + 1;
				Q.push(pii(p, q));
			}
		}
	}
	for(int x = 0; x < n; x++) {
		for(int y = 0; y < m; y++) {
			if(s[x][y] == '#') continue;
			if(inside(x-1, y) && s[x-1][y] != '#') {
				cell[0][x][y] = cell[0][x-1][y];
			} else cell[0][x][y] = pii(x, y);

			if(inside(x, y-1) && s[x][y-1] != '#') {
				cell[1][x][y] = cell[1][x][y-1];
			} else cell[1][x][y] = pii(x, y);
		}
	}
	for(int x = n-1; x >= 0; x--) {
		for(int y = m-1; y >= 0; y--) {
			if(s[x][y] == '#') continue;
			if(inside(x+1, y) && s[x+1][y] != '#') {
				cell[2][x][y] = cell[2][x+1][y];
			} else cell[2][x][y] = pii(x, y);

			if(inside(x, y+1) && s[x][y+1] != '#') {
				cell[3][x][y] = cell[3][x][y+1];
			} else cell[3][x][y] = pii(x, y);
		}
	}
	priority_queue <node> PQ;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			if(s[i][j] == 'S') {
				dis[i][j] = 0;
				PQ.push(node(i, j, 0));
			} else {
				dis[i][j] = inf;
			}
		}
	}
	while(!PQ.empty()) {
		node h = PQ.top();
		PQ.pop();
		for(int i = 0; i < 4; i++) {
			int x = h.x + dx[i];
			int y = h.y + dy[i];
			if(inside(x, y) && s[x][y] != '#') {
				if(dis[x][y] > 1 + dis[h.x][h.y]) {
					dis[x][y] = 1 + dis[h.x][h.y];
					PQ.push(node(x, y, dis[x][y]));
				}
			}
			int p = cell[i][h.x][h.y].first;
			int q = cell[i][h.x][h.y].second;
			if(dis[p][q] > dis[h.x][h.y] + d[h.x][h.y] + 1) {
				dis[p][q] = dis[h.x][h.y] + d[h.x][h.y] + 1;
				PQ.push(node(p, q, dis[p][q]));
			}
		}
	}
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			if(s[i][j] == 'C') {
				printf("%d\n", dis[i][j]);
			}
		}
	}
	return 0;
}

Compilation message (stderr)

portals.cpp: In function 'int main(int, const char**)':
portals.cpp:31:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
portals.cpp:33:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s", s[i]);
   ~~~~~^~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 19 / 19
• Subtask 5: 30 / 30