ricehub.cpp: In member function 'void prefix_sum::build(std::vector<long long int>)':
ricehub.cpp:22:667: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
22 | int ceildiv(int one, int two) {if (one % two == 0) {return one / two;}else {return one / two + 1;}} int power(int n, int pow, int m) {if (pow == 0) return 1;if (pow % 2 == 0) {ll x = power(n, pow / 2, m);return (x * x) % m;}else return (power(n, pow - 1, m) * n) % m;} int gcd(int a, int b) { if (!b)return a; return gcd(b, a % b);} int factorial(int n, int mod) {if (n > 1)return (n * factorial(n - 1, mod)) % mod; else return 1;} int lcm(int a, int b) {return (a * b) / gcd(a, b);} vector<int> read(int n) {vector<int> a; for (int i = 0; i < n; i++) { int x; cin >> x; a.pb(x);} return a;}struct prefix_sum{vint pref;void build(vint a){pref.pb(0);for(int i = 0; i < a.size(); i++){pref.pb(pref.back()+a[i]);}}int get(int l, int r){return pref[r]-pref[l-1];}};//ssense
| ~~^~~~~~~~~~
ricehub.cpp: In function 'long long int besthub(long long int, long long int, long long int*, long long int)':
ricehub.cpp:55:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
55 | int mid = l+r>>1;
| ~^~
/usr/bin/ld: /tmp/cc2SvvGv.o: in function `main':
grader.cpp:(.text.startup+0xae): undefined reference to `besthub(int, int, int*, long long)'
collect2: error: ld returned 1 exit status