제출 #92080

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
92080		arman_ferdous	Mecho (IOI09_mecho)	C++17	45 / 100	544 ms	66560 KiB

mecho

#include <bits/stdc++.h>
using namespace std;
 
typedef pair<int,int> ii;
const int N = 1001;
const int inf = 2e9;
 
int n, S, d[N][N], dist[N][N];
char s[N][N];
queue<ii> q;
ii mecho, home;
 
int dx[] = {1,0,-1,0};
int dy[] = {0,1,0,-1};
 
bool can(int T) {
	for(int i = 0; i < n; i++)
		for(int j = 0; j < n; j++)
			dist[i][j] = inf;
	if(T * S >= d[mecho.first][mecho.second]) return false;
 
	q.push(mecho);
	dist[mecho.first][mecho.second] = T * S;
	ii u; int arrival, tx, ty;
	while(!q.empty()) {
		u = q.front(); q.pop();
		for(int i = 0; i < 4; i++) {
			tx = u.first + dx[i], ty = u.second + dy[i];
			if(min(tx,ty) < 0 || max(tx,ty) >= n) continue;
			if(s[tx][ty] != 'G' && s[tx][ty] != 'D') continue;
			arrival = dist[u.first][u.second] + 1;
			if(arrival >= d[tx][ty] || arrival > dist[tx][ty]) continue;
			dist[tx][ty] = dist[u.first][u.second] + 1;
			q.push({tx,ty});
		}
	} 
	return dist[home.first][home.second] != inf;
}
 
int main() {
	scanf("%d %d", &n, &S);
	for(int i = 0; i < n; i++)
		scanf(" %s", s[i]);
 
	for(int i = 0; i < n; i++)
		for(int j = 0; j < n; j++) {
			d[i][j] = inf;
			if(s[i][j] == 'M') mecho = {i,j};
			else if(s[i][j] == 'D') home = {i,j};
		}
	s[mecho.first][mecho.second] = 'G';
 
	for(int i = 0; i < n; i++)
		for(int j = 0; j < n; j++) 
			if(s[i][j] == 'H') {
				q.push({i,j});
				d[i][j] = 0;
			}
 
	while(!q.empty()) {
		ii u = q.front(); q.pop();
		for(int i = 0; i < 4; i++) {
			int tx = u.first + dx[i], ty = u.second + dy[i];
			if(min(tx,ty) < 0 || max(tx,ty) >= n) continue;
			if(s[tx][ty] != 'G') continue;
			if(d[tx][ty] < d[u.first][u.second] + S) continue;
			d[tx][ty] = d[u.first][u.second] + S;
			q.push({tx,ty});
		}
	}
	int lo = 0, hi = n * n, ans = -1;
	while(lo <= hi) {
		int mid = (lo + hi) >> 1;
		if(can(mid)) ans = mid, lo = mid+1;
		else hi = mid-1;
	} printf("%d\n", ans);
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

mecho.cpp: In function 'int main()':
mecho.cpp:41:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &S);
  ~~~~~^~~~~~~~~~~~~~~~~
mecho.cpp:43:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf(" %s", s[i]);
   ~~~~~^~~~~~~~~~~~~

• Subtask 1: 45 / 100