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- #include <iostream>
- #include <queue>
- #include <vector>
- using namespace std;
- int main() {
- int n, m;
- cin >> n >> m;
- char mat[n][m];
- int si, sj, ei, ej;
- for(int i = 0; i < n; i++) {
- for(int j = 0; j < m; j++) {
- cin >> mat[i][j];
- if(mat[i][j] == 'S') {
- si = i;
- sj = j;
- }
- if(mat[i][j] == 'E') {
- ei = i;
- ej = j;
- }
- }
- }
- queue<int> q;
- q.push(si);
- q.push(sj);
- q.push(0);
- int di[] = {-1, 1, 0, 0};
- int dj[] = {0, 0, -1, 1};
- vector<vector<bool>> visited(n, vector<bool>(m, false));
- vector<vector<int>> dist_from_S(n, vector<int>(m, -1));
- vector<vector<int>> dist_from_E(n, vector<int>(m, -1));
- while(!q.empty()) {
- int ci = q.front();
- q.pop();
- int cj = q.front();
- q.pop();
- int dist = q.front();
- q.pop();
- if(ci == ei and cj == ej) {
- cout << dist << endl;
- return 0;
- }
- if(mat[ci][cj] == '#') {
- dist_from_S[ci][cj] = dist;
- continue;
- }
- for(int i = 0; i < 4; i++) {
- int ti = ci + di[i];
- int tj = cj + dj[i];
- if(ti >= 0 and ti < n and tj >= 0 and tj < m and !visited[ti][tj]) {
- q.push(ti);
- q.push(tj);
- q.push(dist + 1);
- visited[ti][tj] = true;
- }
- }
- }
- for(int i = 0; i < n; i++) {
- for(int j = 0; j < m; j++) {
- visited[i][j] = false;
- }
- }
- q.push(ei);
- q.push(ej);
- q.push(0);
- while(!q.empty()) {
- int ci = q.front();
- q.pop();
- int cj = q.front();
- q.pop();
- int dist = q.front();
- q.pop();
- if(mat[ci][cj] == '#') {
- dist_from_E[ci][cj] = dist;
- continue;
- }
- for(int i = 0; i < 4; i++) {
- int ti = ci + di[i];
- int tj = cj + dj[i];
- if(ti >= 0 and ti < n and tj >= 0 and tj < m and !visited[ti][tj]) {
- q.push(ti);
- q.push(tj);
- q.push(dist + 1);
- visited[ti][tj] = true;
- }
- }
- }
- int res = -1;
- for(int i = 0; i < n; i++) {
- for(int j = 0; j < m; j++) {
- if(mat[i][j] == '#' and dist_from_S[i][j] != -1 and dist_from_E[i][j] != -1) {
- res = max(res, dist_from_S[i][j] + dist_from_E[i][j]);
- }
- }
- }
- cout << res << endl;
- return 0;
- }
- /*
- P.#K#
- .##.#
- .....
- .....
- **/
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