#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define ins insert
#define pb push_back
#define endl '\n'
#define putr(x) cout<<x<<endl;return;
#define all(x) x.begin(),x.end()
const int mod = 1e9 +7, sze = 1e5 +5, inf = INT_MAX, LL = 30;
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
int comp[4005][4005];
unordered_map<int,int> edg[4005];
const int dx[4] = {-1,1,0,0};
const int dy[4] = {0,0,-1,1};
void rush(){
int n,m;
cin>>n>>m;
vector<vector<char>> arr(n,vector<char>(m));
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
comp[i][j]=-1;
cin>>arr[i][j];
}
}
int ct = 0;
int u,v,a,b;
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
if(arr[i][j]!='.' && comp[i][j]==-1){
queue<pair<int,int>> q;
q.push({i,j});
comp[i][j]=ct;
while(!q.empty()){
pair<int,int> node = q.front();q.pop();
for(int x=0;x<4;x++){
a = node.first + dx[x];
b = node.second + dy[x];
if(a>=0 && a<n && b>=0 && b<m && comp[a][b]==-1 && arr[a][b]==arr[i][j]){
comp[a][b]=ct;
q.push({a,b});
}
}
}
ct++;
}
}
}
vector<int> graph[ct];
for(int i =0;i<n;i++){
for(int j=0;j<m;j++){
if(comp[i][j]!=-1){
for(int x= 0; x<4;x++){
a = i + dx[x];
b = j + dy[x];
if(a>=0 && a<n && b>=0 && b<m && comp[a][b] !=-1 && comp[a][b]!=comp[i][j]){
u = min(comp[i][j],comp[a][b]);
v =max(comp[i][j],comp[a][b]);
if(edg[u][v]==0 ){
edg[u][v]=1;
graph[u].pb(v);
graph[v].pb(u);
}
}
}
}
}
}
int ans=0;
queue<pair<int,int>> q;
vector<int> used(ct,0);
q.push({0,1});
used[0]=1;
while(!q.empty()){
auto node = q.front();
ans=max(ans,node.second);
q.pop();
for(auto v:graph[node.first]){
if(!used[v]){
used[v]=1;
q.push({v,node.second+1});
}
}
}
putr(ans);
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int tt = 1;
// cin>>tt;
while(tt--){
rush();
}
return 0;
}
Compilation message
In file included from /usr/include/x86_64-linux-gnu/c++/10/bits/gthr.h:148,
from /usr/include/c++/10/ext/atomicity.h:35,
from /usr/include/c++/10/bits/ios_base.h:39,
from /usr/include/c++/10/ios:42,
from /usr/include/c++/10/istream:38,
from /usr/include/c++/10/sstream:38,
from /usr/include/c++/10/complex:45,
from /usr/include/c++/10/ccomplex:39,
from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
from tracks.cpp:3:
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:102:1: error: attribute value 'tune=native' was already specified in 'target' attribute
102 | __gthrw(pthread_once)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:102:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:103:1: error: attribute value 'tune=native' was already specified in 'target' attribute
103 | __gthrw(pthread_getspecific)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:103:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:104:1: error: attribute value 'tune=native' was already specified in 'target' attribute
104 | __gthrw(pthread_setspecific)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:104:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:106:1: error: attribute value 'tune=native' was already specified in 'target' attribute
106 | __gthrw(pthread_create)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:106:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:107:1: error: attribute value 'tune=native' was already specified in 'target' attribute
107 | __gthrw(pthread_join)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:107:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:108:1: error: attribute value 'tune=native' was already specified in 'target' attribute
108 | __gthrw(pthread_equal)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:108:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:109:1: error: attribute value 'tune=native' was already specified in 'target' attribute
109 | __gthrw(pthread_self)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:109:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:110:1: error: attribute value 'tune=native' was already specified in 'target' attribute
110 | __gthrw(pthread_detach)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:110:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:112:1: error: attribute value 'tune=native' was already specified in 'target' attribute
112 | __gthrw(pthread_cancel)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:112:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:114:1: error: attribute value 'tune=native' was already specified in 'target' attribute
114 | __gthrw(sched_yield)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:114:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:116:1: error: attribute value 'tune=native' was already specified in 'target' attribute
116 | __gthrw(pthread_mutex_lock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:116:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:117:1: error: attribute value 'tune=native' was already specified in 'target' attribute
117 | __gthrw(pthread_mutex_trylock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:117:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:119:1: error: attribute value 'tune=native' was already specified in 'target' attribute
119 | __gthrw(pthread_mutex_timedlock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:119:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:121:1: error: attribute value 'tune=native' was already specified in 'target' attribute
121 | __gthrw(pthread_mutex_unlock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:121:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:122:1: error: attribute value 'tune=native' was already specified in 'target' attribute
122 | __gthrw(pthread_mutex_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:122:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:123:1: error: attribute value 'tune=native' was already specified in 'target' attribute
123 | __gthrw(pthread_mutex_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:123:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:125:1: error: attribute value 'tune=native' was already specified in 'target' attribute
125 | __gthrw(pthread_cond_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:125:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:126:1: error: attribute value 'tune=native' was already specified in 'target' attribute
126 | __gthrw(pthread_cond_broadcast)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:126:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:127:1: error: attribute value 'tune=native' was already specified in 'target' attribute
127 | __gthrw(pthread_cond_signal)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:127:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:128:1: error: attribute value 'tune=native' was already specified in 'target' attribute
128 | __gthrw(pthread_cond_wait)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:128:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:129:1: error: attribute value 'tune=native' was already specified in 'target' attribute
129 | __gthrw(pthread_cond_timedwait)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:129:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:130:1: error: attribute value 'tune=native' was already specified in 'target' attribute
130 | __gthrw(pthread_cond_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:130:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:132:1: error: attribute value 'tune=native' was already specified in 'target' attribute
132 | __gthrw(pthread_key_create)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:132:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:133:1: error: attribute value 'tune=native' was already specified in 'target' attribute
133 | __gthrw(pthread_key_delete)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:133:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:134:1: error: attribute value 'tune=native' was already specified in 'target' attribute
134 | __gthrw(pthread_mutexattr_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:134:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:135:1: error: attribute value 'tune=native' was already specified in 'target' attribute
135 | __gthrw(pthread_mutexattr_settype)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:135:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:136:1: error: attribute value 'tune=native' was already specified in 'target' attribute
136 | __gthrw(pthread_mutexattr_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:136:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:237:10: error: attribute value 'tune=native' was already specified in 'target' attribute
237 | __gthrw2(__gthrw_(__pthread_key_create),
| ^~~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:237:10: error: attribute value 'tune=native' was already specified in 'target' attribute
