View Compilation Error

0_0_17975087_5372.cpp: In function 'void dfs(int)':
0_0_17975087_5372.cpp:14:55: error: 'max' was not declared in this scope
                  f[x][j]=max(f[x][j],f[x][j-k]+f[v][k]);
                                                       ^
0_0_17975087_5372.cpp: In function 'int KM()':
0_0_17975087_5372.cpp:26:9: error: 'ps' was not declared in this scope
   ps(a,b); ps(b,a); 
         ^
0_0_17975087_5372.cpp:28:9: error: too many arguments to function 'void dfs(int)'
  dfs(1,0);
         ^
0_0_17975087_5372.cpp:5:6: note: declared here
 void dfs(int x){
      ^