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| #include <bits/stdc++.h>
using namespace std;
const int LEN = 2500;
int n, m, walk[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
bool ans;
char arr[LEN][LEN];
struct node {
bool vis_;
int nx_, ny_;
} vis[LEN][LEN];
void dfs(int x, int y, int nx, int ny) {
if (ans) return;
x = (x + n) % n, y = (y + m) % m;
if (arr[x][y] == '#') return;
if (vis[x][y].vis_) {
if ((vis[x][y].nx_ != nx || vis[x][y].ny_ != ny)) ans = true;
return;
}
vis[x][y].vis_ = 1, vis[x][y].nx_ = nx, vis[x][y].ny_ = ny;
for (int i = 0; i < 4; ++i) {
dfs(x + walk[i][0], y + walk[i][1], nx + walk[i][0], ny + walk[i][1]);
}
}
int main() {
int x, y;
while (cin >> n >> m) {
ans = false;
memset(vis, 0, sizeof(vis));
for (int i = 0; i < n; ++i)
for (int j = 0; j < m; ++j) {
cin >> arr[i][j];
if (arr[i][j] == 'S') x = i, y = j;
}
dfs(x, y, x, y);
cout << (ans ? "Yes" : "No") << endl;
}
return 0;
}
|
