In the question june codechef starters Flappy Bird (link-https://www.codechef.com/START5B/problems/FLAPPYBD)

ihave written a solution but unfortunataly it is wrong i am not able to get why.

If anyone can help it would be of great help.Any help will be appreciated.

Link to sol-https://www.codechef.com/viewsolution/48300736

(Code is provided below too)

What i did is first checked if anywhere this game cannot be completed (used variable value for it).

If not then i moved step by step from starting position to X1, then from X1 to X2 and so on.

I took the minimum clicks tp reach Xi but if anytime it cant move forward i adjusted the number of clicks(clicks which i havent used earlier where i could have). Variable c refers to clicks needed to go from Xi to Xi+1, click is used to fnd total no of clicks.

Thank you.

```
using namespace std;
int gcd(int a,int b){
if(a%b==0)
return b;
else
return gcd(b,a%b);
}
void solve(){
int t;
cin>>t;
while(t--){
int n,H;
cin>>n>>H;
int x[n];
int h[n];
int value=0;
for(int i=0;i<n;i++)
cin>>x[i];
for(int i=0;i<n;i++) {
cin >> h[i];
if(h[i]>=x[i]+H)
value=-1;
}
int height=H;
int clicks=0;
int pos=0;
for(int i=0;i<n;i++) {
int c=ceil(double(h[i]+1+x[i]-pos-height)/2);
if(c>0){
if(c>x[i]-pos){
if(pos-clicks>c-x[i]+pos) {
clicks=clicks+c;
pos = x[i];
height = h[i] + 1;
}
else{
value=-1;
pos = x[i];
height = h[i] + 1;
}
}
else{
clicks=clicks+c;
pos=x[i];
height=h[i]+1;
}
}
else {
int dist=x[i]-pos;
if(height-dist>=h[i]+1){
pos=x[i];
height=height-dist;
}
}
}
if(value==-1) {
cout<<-1<<"\n";
goto label;
}
cout<<clicks<<"\n";
label:;
}
}
int main(){
#ifndef ONLINE_JUDGE
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
freopen("error.txt","w",stderr);
#endif
ios_base::sync_with_stdio(false);
cin.tie(NULL);
solve();
return 0;
}
```