Compilare: user.cpp: In function ‘void ReduceGraph()’: user.cpp:68:29: warning: unused variable ‘v’ [-Wunused-variable] int v = *it2; ^ user.cpp: In function ‘void ReadTestData()’: user.cpp:26:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:31:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int u, v; scanf("%d%d", &u, &v); ^ user.cpp: In function ‘int main()’: user.cpp:119:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(scanf("%d", &test_count); test_count > 0; test_count--) { ^