View Compilation Error

0_0_17974999_29895.cpp: In function 'void dfs(int)':
0_0_17974999_29895.cpp:6:14: error: 'i' was not declared in this scope
  int cost=(s[i]+19)/20;
              ^
0_0_17974999_29895.cpp:13:8: error: 'k' was not declared in this scope
    for(k=1; k<=j-cost; k++)
        ^
0_0_17974999_29895.cpp:13:16: error: 'j' was not declared in this scope
    for(k=1; k<=j-cost; k++)
                ^
0_0_17974999_29895.cpp:14:38: error: 'dp' was not declared in this scope
                  f[x][j]=max(f[x][j],dp[x][j-k]+dp[v][k]);
                                      ^
0_0_17974999_29895.cpp:14:57: error: 'max' was not declared in this scope
                  f[x][j]=max(f[x][j],dp[x][j-k]+dp[v][k]);
                                                         ^
0_0_17974999_29895.cpp:16:9: error: a function-definition is not allowed here before '{' token
 int KM(){
         ^
0_0_17974999_29895.cpp:31:26: error: expected '}' at end of input
 int main(){ while(KM()); }
                          ^