View Compilation Error

0_0_15685128_14343.cpp: In function 'void spfa()':
0_0_15685128_14343.cpp:66:18: error: 'u' was not declared in this scope
  for(int i = fst[u]; ~i; i = nxt[i]) {
                  ^
0_0_15685128_14343.cpp:72:12: error: a function-definition is not allowed here before '{' token
 int main() {
            ^
0_0_15685128_14343.cpp:115:9: error: expected '}' at end of input
   spfa();
         ^
0_0_15685128_14343.cpp:115:9: error: expected '}' at end of input