I am not able to follow the solution completely. Suppose if the testcase is
6
8 geography
3 Maths
9 english
-1
-1
-1
this is i think a valid testcase but with the solution explained in editorials, i dont think the answer would be right as we have never pushed english on the stack and the last -1 wont be properly answered. Could you please explain this? thanks
Can anyone figure out why my code is getting WA? I am using two stacks- one for storing the pile of books in a general fashion and the other is a special stack which has the minimum number of exercises in any book present in stack 1.Every time a new book is pushed in stack 1, i am checking if the top of stack 2 has a book that has left exercises greater than that new book- if yes then that book is even pushed in the 2nd stack,otherwise ignored. In case of a query i am counting …i pop the topmost book from stack 2 and keep poping the books from stack 1 until that book matches.I have tried all sample test cases that i could find anywhere and my code is giving the correct output but the judge rules it out.
Any help would be hoghly appreciated.
Here is the link~~ CodeChef: Practical coding for everyone
awesome…
can someone tell why i am getting runtime error sigsegv… my code is here:
http://www.codechef.com/viewsolution/3599271
I tried the same algorithm as author’s using both vector and stack data type. I am getting correct answers for small test cases, but TLE on submission. Could someone help out?
https://www.codechef.com/viewsolution/8924342
struct Book
{
char name[16];
int booksOnTop;
int exercisesLeft;
Book()
{
}
Book(char *_name, int _exercisesLeft)
: booksOnTop(0), exercisesLeft(_exercisesLeft)
{
strcpy(name, _name);
}
};
int main()
{
int n, ex;
std::stack nextMin;
char name[16];
scanf("%d", &n);
while (n--)
{
scanf("%d", &ex);
if (ex != -1)
{
scanf("%s", name);
if (ex == 0)
continue;
if (nextMin.size() == 0)
nextMin.push(Book(name, ex));
else
{
Book& b = nextMin.top();
if (b.exercisesLeft >= ex)
nextMin.push(Book(name, ex));
else
b.booksOnTop++;
}
}
else
{
Book b = nextMin.top();
nextMin.pop();
printf("%d %s\n", b.booksOnTop, b.name);
}
}
return 0;
}
I tried your code and I’m getting RE - BGO4YF - Online C++ Compiler & Debugging Tool - Ideone.com
I tried correctness of the input with tester’s solution - http://ideone.com/Yy98Ow
Try this two test cases:
5
8 a
6 b
-1
7 c
-1
6
8 a
6 b
-1
7 c
-1
-1Thank you, with your help, I fixed the bug caused RE. However, the new code have a unexpected TLE error while I thought its time complexity is O(N), can you give me a hint?
The problem is that you are using cin and it is slow, replace cin with scanf and it will get AC 
@jigsaw004: reading someone’s code is good practice for challenges (for example fot TopCoder or CodeForces competitions). hacker007’s code is really well written and short, it’s bigger problem with longer codes
my code is showing SIGSEV error … if it due to large memory … then why it is not showing for tester solution … i have also used same type of arrays having same size … here is link to my code
http://www.codechef.com/viewsolution/1650094
figured the mistake… we can declare at max 10 power 5 size array in c functions… so to declare 10 power 6 size we must declare the array as a global array.
could anyone tell why i am getting the WA?
here’s my code:-
l = []
nm = []
cnt = 0
t = int(input())
for _ in range(t):
s = list(input().split(" "))
if(int(s[0]) != -1):
rm = int(s[0])
if(len(l) == 0):
l.append(int(s[0]))
nm.append(s[1])
elif rm > l[-1]:
cnt = cnt + 1
else:
l.append(int(s[0]))
nm.append(s[1])
else:
print(cnt,nm.pop())
l.pop()
cnt = 0
Somebody please help me.
My code is passing the test cases given in the question. But it’s still giving wrong answer.
#include <bits/stdc++.h>
using namespace std;
int main() {
unsigned int n;
cin>>n;
stack stack2;
stack stack1;
int books_on_top=0;
while(n–){
int num;
cin>>num;
if(num!=-1){
string s;
cin>>s;
if(num==0){
continue;
}
if(stack1.empty()){
stack1.push(num);
stack2.push(s);
}
else if(num<=stack1.top()){
stack1.push(num);
stack2.push(s);
}
else{
books_on_top++;
}
}
else if(num==-1){
if(stack2.empty()){
cout<<books_on_top<<"\n";
}
else{
cout<<books_on_top<<" "<<stack2.top()<<"\n";
stack1.pop();
stack2.pop();
books_on_top=0;
}
}
}
return 0;
}
I tried these test cases and my code passing them.
But when I submit, I still get wrong answer.
#include <bits/stdc++.h>
using namespace std;
int main() {
unsigned int n;
cin>>n;
stack stack2;
stack stack1;
int books_on_top=0;
while(n–){
int num;
cin>>num;
if(num!=-1){
string s;
cin>>s;
if(num==0){
continue;
}
if(stack1.empty()){
stack1.push(num);
stack2.push(s);
}
else if(num<=stack1.top()){
stack1.push(num);
stack2.push(s);
}
else{
books_on_top++;
}
}
else if(num==-1){
if(stack2.empty()){
cout<<books_on_top<<"\n";
}
else{
cout<<books_on_top<<" "<<stack2.top()<<"\n";
stack1.pop();
stack2.pop();
books_on_top=0;
}
}
}
return 0;
}
this test case is not valid,
after the first query of type (-1), only one element is left in the stack and that is 8 geography.
after the second query of type (-1), stack is empty. and hence third -1 makes the test case invalid.
please provide a test case, where my code gives WA.
#include <bits/stdc++.h>
using namespace std;
int32_t main()
{
ios_base ::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int n, x;
string s;
stack<pair<int, pair<int, string>>> st;
int min = INT_MAX;
cin >> n;
while (n--)
{
cin >> x;
if (x == -1)
{
int cnt = 0;
//cout << st.top().first << " ";
while (st.top().first != st.top().second.first)
{
cnt++;
st.pop();
}
cout << cnt << " " << st.top().second.second << "\n";
st.pop();
if (!st.empty())
{
min = st.top().first;
}
else
{
min = INT_MAX;
}
}
else
{
cin >> s;
if (min > x)
{
min = x;
}
st.push({min, {x, s}});
}
}
return 0;
}
can someone give an example for test case 6 ?
my code goes through the other test cases and i tried to find a case where my code gives wrong answer
or does anybody see where my code does wrong ?