View Compilation Error

0_0_32863824_27722.cpp: In function 'void dfs2(int)':
0_0_32863824_27722.cpp:3:19: error: 'xs' was not declared in this scope
     for(int i=0;i<xs[u].size();i++)
                   ^
0_0_32863824_27722.cpp:7:9: error: 'dp' was not declared in this scope
         dp[to][2]=max(dp[u][2],dp[to][0]+val==dp[u][0]?dp[u][1]:dp[u][0])+val;
         ^
0_0_32863824_27722.cpp:7:73: error: 'max' was not declared in this scope
         dp[to][2]=max(dp[u][2],dp[to][0]+val==dp[u][0]?dp[u][1]:dp[u][0])+val;
                                                                         ^