Interesting Selection

problem statement is here

here we have two possibilities
        (1). we take cold drink from 1st position
        (2). we take poison from 1st position
rest can be easily calculated using dp


#include<stdio.h>
long long ar[100006],br[100007];
long long max(long long a,long long b){
if(a>b){
return a;
}else{
return b;
}
}
long long check(long long a,long long b){

if(a>b){
return 0;
}
long long cr[b+1],i;
cr[a]=ar[a];
cr[a-1]=0;
for(i=a+1;i<=b;i++){
cr[i]=max((cr[i-2]+ar[i]-br[i-1]),cr[i-1]-br[i]);
}
return cr[b];
}
int main(){
long long a,b,c,i,j,n,x,y,z;
int t;
scanf("%d",&t);
while(t--){
scanf("%lld",&n);
for(i=0;i<n;i++){
scanf("%lld",&ar[i]);
}
for(i=0;i<n;i++){
scanf("%lld",&br[i]);
}
if(n==1){
x=ar[0];
}else if(n==2){
x=max(ar[0]-br[1],ar[1]-br[0]);
}else{
y=ar[0]-br[n-1]-br[1]+check(2,n-2);
z=check(1,n-1)-br[0];
x=max(y,z);
}
printf("%lld\n",x);
}
return 0;
}