Why my code isn't working

Question

https://code.sololearn.com/cPtTlJ9n9Dsf/?ref=app
https://www.sololearn.com/post/945927/?ref=app

Answer 1

I don't get what you are doing in your code .

and do you realise you are accessing negative index and array out of bound index ?

you just need to do
cin>>arr[i]
b[arr[i]]++

Answer 2

Roy Kapoor I don't even know what you are trying to do at all. I showed yesterday exactly how to do it or just an idea of what arsenic was talking about .

You should honestly go for small problems if you aren't ready for these yet . I know my solution would have been hard to understand but it's all about understanding what is asked in question and if you have basic understanding of language , nothing difficult when it comes to implementation.

I see these two lines here,

b[n]=0*n;
}
for(int i=0;i<a[n];i++)

what is "0*n" and "i<a[n]" ???
Also did you realised in "b[n]" n never changes .

Answer 3

// simplified + functional version:

#include <iostream>
using namespace std;

int solve(int n) {
int i, x, b[n], f = 1;
for (i=0; i<n; ++i) b[i] = 0;
for (i=0; i<2*n; ++i) {
cin >> x;
if (0<x && x<=n && ++b[--x]<3)
continue;
f = 0; break;
}
return f;
}

int main() {
int t, n;
cin >> t;
while (t--) {
cin >> n;
n = solve(n);
cout << (n ? "Yes" : "No ") << endl;
}
}

Answer 4

Roy Kapoor
arr1=[0]*n
int arr1[n]={} // C++ version

and you have got it all wrong.

Do you know how a for loop in python works ?

You have just put the same thing in cpp but that's now how you do it .

Answer 5

Oh, you're right...
fixed version here:

https://code.sololearn.com/cdjhEm9h5NOE/?ref=app

Answer 6

Actually I made it in py..and was trying to make it in cpp..

t = int(input())
while t:
n = int(input())
arr = list(map(int, input().split()))
arr1 = [0]*n
for i in arr:
arr1[i-1] += 1
for i in arr1:
if i is not 2:
print('NO')
break
else:
print('YES')
t -= 1

Answer 7

Thanks Abhay,Hima

Answer 8

Visph your code is perfect but fails for testcases above 3

2
3
1 2 3 2 1 3
4
1 2 3 2 1 2 3 4
2
1 1 2 3
1
1 1

Output:
YES
NO
NO
NO