[pan Wai 1] Huawei computer test

note1. again!
ctrl + F + again! to find the problems that need a double check

hj7. casting
float i;
int j = (int) i;

hj9. unordered_set
unordered_set
reverse(str.begin(), str.end())
set.count
set.insert

hj46. sub string
string s;
s.substr(0, 3); // 3 is not included

hj58. sort vector
vector v;
sort(v.begin(), v.end());

hj2. getline
string array;
getline(cin, array); // this gets more than cin

hj5. ASCII
‘0’ is ASCII 48
‘A’ is ASCII 65
if (s[i] >= ‘0’ && s[i] <= ‘9’)
ans += base * ((int)(s[i]-55));

hj6. prime factor
again!

hj8. map
map<int, int> m;
map<int, int>::iterator it;
it = m.find(a);
m[a] = it->second + b;
it=m.begin(); it!=m.end();it++

hj15. bitset and binary
bitset<32> b(5);
int ans = b.count(); // number of bits that are set
// in this case ans = 2

hj21. password and string.find()
// don’t ever try to to_string(char) because it turns it into its ASCII value
// check https://www.geeksforgeeks.org/string-find-in-cpp/

hj22. a strange question
again!

hj23. a very good practice question
again!

hj31. how to reverse words in a string?
again!