View Compilation Error

0_0_24802385_8197.cpp: In function 'int main()':
0_0_24802385_8197.cpp:19:21: error: 'sort' was not declared in this scope
   sort(p+1,p+n+1,cmp);
                     ^
0_0_24802385_8197.cpp:27:49: error: expected ')' before ';' token
     dp[i][i]=min(dp[i][i],dp[i-1][j]+p[i].second;
                                                 ^
0_0_24802385_8197.cpp:29:12: error: 'inf' was not declared in this scope
   long ans=inf;
            ^