#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define ld long double
#define forn(i,j) for(ll i = 0; i < j; i++)
#define forrange(i,j,k) for(int i = j; i < k; ++i)
#define rof(i,j) rof(int i = j; i >= 0; --i)
#define pii pair<int,int>
#define vll vector<ll>
#define vi vector<int>
#define vvll vector<vll>
#define vvi vector<vi>
#define pb push_back
#define p push
#define f first
#define s second
#define all(x) x.begin(), x.end()
#define eb emplace_back
#define debug(x) cerr << #x << " is " << x << endl;
#define MOD 1000000007
const int N = 4e3;
string grid[N];
int cost(pii a, pii b){
if(grid[a.f][a.s] != grid[b.f][b.s]){
return 1;
}
else{
return 0;
}
}
int main(){
ios.base::sync_with_stdio(0);
cin.tie(0);
int dx[] = {1,0,-1,0};
int dy[] = {0,1,0,-1};
int h,w;
cin >> h >> w;
vvi dp(h, vi(w, 0));
forn(i,h){
cin >> grid[i];
}
deque<pii> s;
dp[0][0] = 1;
s.push_back({0,0});
int mx = 0;
while(!s.empty()){
pii k = s.front();
s.pop_front();
mx = max(dp[k.f][k.s], mx);
forn(i,4){
int m = k.f + dx[i];
int n = k.s + dy[i];
pii g = {m,n};
if((m < 0 || n < 0 || m >= h || n >= w) || grid[m][n] == '.' || dp[m][n] != 0){
continue;
}
else{
if(cost(g,k) == 1){
dp[m][n] = dp[k.f][k.s] + 1;
s.push_back(g);
}
else{
dp[m][n] = dp[k.f][k.s];
s.push_front(g);
}
}
}
}
cout << mx << endl;
}
Compilation message
tracks.cpp: In function 'int main()':
tracks.cpp:42:5: error: expected unqualified-id before '.' token
42 | ios.base::sync_with_stdio(0);
| ^
