# getting nzec.. plz help...

I tried to run this program for the primedistance question asked in august 13 challenge… I just visited every node and checked it’s distance from every other node… it’s giving correct answers for some test cases that I tried but on submitting it, it’s showing nzec error… help plz… here’s the code…

`````` class CLASSNAME {
static long total=0;
public void solve(int testNumber, InputReader in, OutputWriter out) {
boolean[][] tree=new boolean[n+1][n+1];
boolean[] isPrime=IntegerUtils.generatePrimalityTable(100001);
boolean[] isVis;
for(int i=1;i<n;i++){
tree[a][b]=tree[b][a]=true;
}

for(int i=1;i<=n;i++){
isVis=new boolean[n+1];
recurse(tree,isPrime,isVis,1,i);
}
//out.printLine(total);
out.printLine((total/2)/((n*(n-1))/2.0));
}
static void recurse(boolean[][] tree,boolean[] isPrime,boolean[] isVis,int sum,int level){
if(isVis[level])return;
isVis[level]=true;
//if(level>=tree[0].length)return;
for(int i=1;i<tree[0].length;i++){
if(tree[level][i]){
if(isPrime[sum] && !isVis[i]){
total++;
//System.out.println(level+" "+i+" "+sum);
}
recurse(tree,isPrime,isVis,sum+1,i);
}
}
}
}``````

``````3
1 2
2 3
``````

returns 0.3333333333333333

while for

``````3
3 2
2 1
``````

it returns 0.0, but it is the same tree…

1 Like

Please remove the tag ‘aug13’ from this. Don’t pollute the AUG13 editorial space.

I changed the code where i am getting input…
for(int i=1;i<n;i++){
tree[Math.min(a,b)][Math.max(a, b)]=true;
}

``````7
1 2
2 3
3 6
3 4
4 5
6 7
``````

?

Graph is:

``````1 - 2 - 3 - 4 - 5
|
6
|
7
``````

your code returns `0.42857142857142855`, but I think it’s 10/21 = `0.4761904`

``````2: 1-3, 2-4, 2-6, 3-5, 3-7, 4-6
3: 1-6, 1-4, 2-5, 2-7
``````

it should be 12/21…isn’t it?
how does it come to 10??

I wrote all “prime paths” and there are 10 above…

you missed out 4-7 and 5-6

you are correct, but you found your problem also, the probability is 12/21 instead of 9/21…

now it’s giving nzec…
check the code…i’ve edited it in the question itself…

editorial tag is for editorials not aug13

1 Like

@betlista- very well said…

1 Like