Code not giving any output, rain water harvesting problem

#1

int cal(int n, int a[])
{
int maxsofar=0,index=0,ptr1=0,ptr2=0,sum=0,diff=0;
for(int i=0;i<n;i++)
{
if(a[i]==0)
{
continue;
}
else
{
ptr1=i;
ptr2=i+1;
maxsofar=0;

			index=i;
		}
	}
if(index==(n-1))
{return 0;}

while(ptr1<n)
{
	if(a[ptr2]>=a[ptr1])
	{
		diff=a[ptr1];
		for(ptr1;ptr1<ptr2;ptr1++)
		{
			sum+= (diff-a[ptr1]);
		}
		//maxsofar=a[ptr2];
		ptr1=ptr2;
		ptr2=ptr2+1;
		maxsofar=0;
	}
	else if(a[ptr2]<a[ptr1])
	{ 
		
		if(a[ptr2]>=maxsofar)
		{
			maxsofar=a[ptr2];
			index=ptr2;
		}
		ptr2++;
	}
	if(ptr2==(n-1))
	{
		if(maxsofar==0)
		{
			return sum;
		}
		else{
			for(ptr1+1;ptr1<index;ptr1++)
		       {
			     sum+= (maxsofar-a[ptr1]);
		      }
			  return sum;
			}
	}

}
return sum;

}

#2

hey, you are using quite clumpsy approach, go for the approach mentioned in course video and try to code it. This is not a typical two pointer problem!

#3

There is no video for this in course, that i know of. Also, i just wanna know that, why is nothing being printed.

#4

Hey,
for(int i=0;i<n;i++)
{
if(a[i]==0)
{
continue;
}
else
{
ptr1=i;
ptr2=i+1;
maxsofar=0;

        index=i;
    }
}

if(index==(n-1))
{return 0;}
Here your index is n-1 always if a[n-1]!=0, so it just returns 0!!
Also refer to this for clear approach

1 Like
#5

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