View Compilation Error

0_0_38173812_16120.cpp: In function 'void dfs(int, int)':
0_0_38173812_16120.cpp:28:11: error: expected unqualified-id before '[' token
  for(auto [a,b]:mpp) ans+=b/2;
           ^
0_0_38173812_16120.cpp:28:11: error: expected ';' before '[' token
0_0_38173812_16120.cpp: In lambda function:
0_0_38173812_16120.cpp:28:16: error: expected '{' before ':' token
  for(auto [a,b]:mpp) ans+=b/2;
                ^
0_0_38173812_16120.cpp: In function 'void dfs(int, int)':
0_0_38173812_16120.cpp:28:16: error: expected ';' before ':' token
0_0_38173812_16120.cpp:28:16: error: expected primary-expression before ':' token
0_0_38173812_16120.cpp:28:16: error: expected ')' before ':' token
0_0_38173812_16120.cpp:28:16: error: expected primary-expression before ':' token