View Compilation Error

0_0_39262001_5493.cpp:12:9: error: expected initializer before 'if'
   12 |         if (res > ans)ans = res;
      |         ^~
0_0_39262001_5493.cpp:13:9: error: expected unqualified-id before 'if'
   13 |         if (u >= n)return;
      |         ^~
0_0_39262001_5493.cpp:14:9: error: expected unqualified-id before 'if'
   14 |         if(a[u].first >= end) {            // 如果有时间看这个节目
      |         ^~
0_0_39262001_5493.cpp:18:9: error: expected unqualified-id before 'else'
   18 |         else {
      |         ^~~~
0_0_39262001_5493.cpp:21:1: error: expected declaration before '}' token
   21 | }
      | ^
0_0_39262001_5493.cpp: In function 'int main()':
0_0_39262001_5493.cpp:33:9: error: 'dfs' was not declared in this scope
   33 |         dfs(0, 0, -1);
      |         ^~~