View Compilation Error

0_0_12350069_7692.cpp: In function `void merge(int, int)':
0_0_12350069_7692.cpp:52: error: expected primary-expression before '<' token
0_0_12350069_7692.cpp:52: error: expected primary-expression before '/' token
0_0_12350069_7692.cpp:52: error: `span' undeclared (first use this function)
0_0_12350069_7692.cpp:52: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_12350069_7692.cpp:52: error: expected primary-expression before '}' token
0_0_12350069_7692.cpp:52: error: expected `;' before '}' token