View Compilation Error

0_0_32863848_3016.cpp:24:13: error: conflicting declaration 'int t'
 int n,m,i,j,t,col[305];
             ^
0_0_32863848_3016.cpp:23:11: note: previous declaration as 'const int t'
 const int t=400;
           ^
0_0_32863848_3016.cpp: In function 'int main()':
0_0_32863848_3016.cpp:29:9: error: decrement of read-only variable 't'
  while(t--){
         ^
0_0_32863848_3016.cpp:40:10: error: 'dfs' was not declared in this scope
     dfs(i);
          ^