Q#1
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
void print(int& t){ //for_each fnc: parameter accept elements T
cout << t << " ";
}
int main() {
vector<int> v;
int num, toPut;
cin >> num;
; i<num; i++) {
cin >> toPut;
v.push_back(toPut);
}
sort(v.begin(), v.end());
for_each(v.begin(), v.end(), print); //calling fnc in for_each
;
}
Q#2
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
void print(int& i){
cout << i << " ";
}
int main() {
vector<int> v;
int size, num;
cin >> size;
; i<size; i++){
cin >> num;
v.push_back(num);
}
int toErase1, toErase2;
cin >> toErase1;
v.erase(v.begin()+toErase1-);
cin >> toErase1 >>toErase2;
toErase1--; toErase2--;
v.erase(v.begin()+toErase1, v.begin()+toErase2); //last one exclusive
cout << v.size() <<endl;
for_each(v.begin(), v.end(), print);
;
}
Q#3: time-out exception
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
vector<int> v;
int size, num, time, target;
cin >> size;
; i<size; i++){
cin >> num;
v.push_back(num);
}
cin >> time;
; t<time; t++){ //start testing each case
cin >> target;
;
for(; i<v.size(); i++){
if(v[i]!=target) continue;
<<endl; break;
}
if(i == v.size()){
; j<v.size(); j++){
<<endl; break;} //should not forget the {} in one-line code
}
}
}
}
Q#4
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <set>
#include <algorithm>
#include <cstdlib>
using namespace std;
int main() {
set<int> s;
int num, enquiryType, item;
cin >> num;
while(num){
cin>>enquiryType;
cin >> item;
switch(enquiryType){
: s.insert(item); break;
: s.erase(item); break;
: {
set<int>::const_iterator p = s.find(item);
if(p!=s.end()) cout << "Yes" <<endl; //cannot use if(p!=NULL); Cz even p == v.end(), v.end()!=NULL;
else cout << "No" <<endl;
break;
}
}
num--;
}
}
Q#5
#include <cstdio>
#include <iostream>
#include <map>
#include <algorithm>
#include <string>
using namespace std;
int main() {
map<string, int> students;
int num, marks, choice;
string name;
cin >> num;
while(num){
cin >> choice >> name;
switch(choice){
: {
cin >> marks;
map<string, int>::iterator p = students.find(name); //stl algorithm needed be called by a STL CONTAINER! NOT STANDALONE!
if(p!=students.end()){ //rmb: after 'find()' algorithm, found if p!=container.end();
&& marks!= && marks!=) students[name] += marks; //container name with key represents the value it contains!
break;
}
&& marks!= && marks!=) students.insert(pair<string, int>(name, marks));
));
break;
}
: {
students.erase(name); break;
}
:{
cout << students[name] <<endl;
}
}
num--;
}
}