Main.cc: In function ‘int main()’: Main.cc:103:24: error: ‘spfa’ was not declared in this scope printf("%d\n", spfa(x, y)); ^~~~ Main.cc:90:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &q); ~~~~~^~~~~~~~~~~~~~~~~ Main.cc:94:11: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &w); ~~~~~^~~~~~~~~~ Main.cc:102:14: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ~~~~~^~~~~~~~~~~~~~~~~