#include <iostream>
#include <vector>
#include <set>
#include <queue>
#include <cmath>
#include <algorithm>
using namespace std;
#define speedup ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#define ll long long
const int MAXN = 4010;
char grid[MAXN][MAXN];
int dist[MAXN][MAXN];
int dX[] = {1, -1, 0, 0};
int dY[] = {0, 0, 1, -1};
int h, w;
bool possibility(int x, int y){
if (x >= 0 && x < h && y >= 0 && y < w && grid[x][y] != '.'){
return true;
}
return false;
}
int main(){
speedup
cin >> h >> w;
for (int i = 0; i < h; i++){
string s; cin >> s;
for (int j = 0; j < w; j++){
grid[i][j] = s[j];
}
}
deque<pair<int, int>> q;
q.push_front({0, 0});
memset(dist, -1, sizeof dist);
dist[0][0] = 1;
int ans = 1;
while (!q.empty()){
auto &[x, y] = q.front(); q.pop_front();
for (int i = 0; i < 4; i++){
int nX = x+dX[i], nY = y+dY[i];
if (possibility(nX, nY) && dist[nX][nY] == -1){
if (grid[nX][nY] == grid[x][y]){
dist[nX][nY] = dist[x][y];
q.push_front({nX, nY});
}else{
dist[nX][nY] = dist[x][y]+1;
q.push_back({nX, nY});
}
}
}
ans = max(ans, dist[x][y]);
}
cout << ans << endl;
return 0;
}
Compilation message
tracks.cpp: In function 'int main()':
tracks.cpp:37:5: error: 'memset' was not declared in this scope
37 | memset(dist, -1, sizeof dist);
| ^~~~~~
tracks.cpp:7:1: note: 'memset' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
6 | #include <algorithm>
+++ |+#include <cstring>
7 | using namespace std;
tracks.cpp:41:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
41 | auto &[x, y] = q.front(); q.pop_front();
| ^
