What do these C operators mean?
- by Melkhiah66
I'm reading the book "Programming Challenges: The Programming Contest Training Manual" and are implementing a problem where I do not understand the use of operators c1 and the comparison if (n&1), someone could help me to know they mean?
this is the example code
#include <stdio.h>
#define MAX_N 300
#define MAX_D 150
long cache[MAX_N/2][2];
void make_cache(int n,int d,int mode)
{
long tmp[MAX_D];
int i,count;
for(i=0;i<MAX_D;i++) tmp[i]=0;
tmp[0]=1;count=0;
while(count<=n)
{
count++;
for(i=(count&1);i<=d;i+=2)
{
if(i)
tmp[i] = tmp[i-1] + tmp[i+1];
else if(!mode)
tmp[0]=tmp[1];
else
tmp[0]=0;
}
if((count&1)==(d&1))
cache[count>>1][mode]=tmp[d];
}
}
int main()
{
int n,d,i;
long sum;
while(1)
{
scanf("%d %d",&n,&d);
if(n&1)
sum=0;
else if(d==1)
sum=1;
else if(n<(d<<1))
sum=0;
else if(n==(d<<1))
sum=1;
else
{
make_cache(n,d,0);
make_cache(n,d,1);
sum=0;
for(i=0;i<=(n>>1);i++)
sum+=cache[i][0]*cache[(n>>1)-i][1];
}
printf("%ld\n",sum);
}
return 0;
}
