UVA 11094 Solution- Continents

UVA 11094 Solution- Continents

/*
uva id: shoaib05
Accepted Time:0.000
Algorithm: DFS
*/

#include<iostream>
#include<string.h>
#include<stack>

using namespace std;
char arr[25][25];
char ch,ch1;
typedef pair<int,int> pii;
pii pr;
int m,n;

int dfs(int x,int y)
{
pr=pii(x,y);
stack<pii> st;
st.push(pr);
int count=0;
arr[x][y]=ch1;
while(!st.empty())
{
pr=st.top();
st.pop();
x=pr.first;
y=pr.second;
count++;
if(x>0 && arr[x-1][y]==ch) //Traverse to Up
{
pr=pii(x-1,y);
st.push(pr);
arr[x-1][y]=ch1;
}
if(x<m && arr[x+1][y]==ch) //Traverse to Down
{
pr=pii(x+1,y);
st.push(pr);
arr[x+1][y]=ch1;
}

if(y>0 && arr[x][y-1]==ch) //Traverse to Left
{
pr=pii(x,y-1);
st.push(pr);
arr[x][y-1]=ch1;
}
if(y<n && arr[x][y+1]==ch) //Traverse to Right
{
pr=pii(x,y+1);
st.push(pr);
arr[x][y+1]=ch1;
}

if(y==0 && arr[x][n]==ch) //Traverse to last columm of the current row
{
pr=pii(x,n);
st.push(pr);
arr[x][n]=ch1;
}
if(y==n && arr[x][0]==ch) //Traverse to first columm of the current row
{
pr=pii(x,0);
st.push(pr);
arr[x][0]=ch1;
}
}
return count;
}

void init(int x,int y)
{
dfs(x,y);
}

int main()
{
int i,j,x,y,max,count;
while(cin>>m>>n)
{
m--;
n--;
for(i=0;i<=m;i++)
cin>>arr[i];
cin>>x>>y;
ch=arr[x][y];
if(ch=='#')
ch1='*';
else
ch1='#';
init(x,y);
max=0;
for(i=0;i<=m;i++)
{
for(j=0;j<=n;j++)
{
if(arr[i][j]==ch)
{
count=dfs(i,j);
if(max<count)
max=count;
}
}
}
cout<<max<<endl;
}
return 0;
}