Compilare: main.cpp: In function 'void add0(int)': main.cpp:17:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 17 | for(int j = 0; j < op[1][x].size(); j++) { | ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'void add(int)': main.cpp:24:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 24 | for(int j = 0; j < op[0][x].size(); j++) { | ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'void upd(int)': main.cpp:34:9: warning: statement has no effect [-Wunused-value] 34 | for(id; id <= x.back(); id += id & (-id)) t[id]++; | ^~ main.cpp: In function 'int get(int)': main.cpp:38:9: warning: statement has no effect [-Wunused-value] 38 | for(id; id >= 1; id -= id & (-id)) c += t[id]; | ^~ main.cpp: At global scope: main.cpp:41:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] 41 | main(){ | ^~~~ main.cpp: In function 'int main()': main.cpp:62:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 62 | for(int i = 0; i < x.size(); i++) { | ~~^~~~~~~~~~ main.cpp:79:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 79 | for(int j = 0; j < seg[x[i]].size(); j++) upd(seg[x[i]][j]); | ~~^~~~~~~~~~~~~~~~~~ main.cpp:81:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 81 | for(int j = 0; j < V[x[i]].size(); j++) ans += (ll)get(V[x[i]][j].f) * V[x[i]][j].s; | ~~^~~~~~~~~~~~~~~~