View Compilation Error

0_0_37738560_6381.cpp: In function 'void build(long long int, long long int, long long int)':
0_0_37738560_6381.cpp:70:11: error: no match for 'operator=' (operand types are 'node' and '<brace-enclosed initializer list>')
     tr[u] = {l, r};
           ^
0_0_37738560_6381.cpp:70:11: note: candidates are:
0_0_37738560_6381.cpp:29:8: note: node& node::operator=(const node&)
 struct node
        ^
0_0_37738560_6381.cpp:29:8: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const node&'
0_0_37738560_6381.cpp:29:8: note: node& node::operator=(node&&)
0_0_37738560_6381.cpp:29:8: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'node&&'