2 replies to this topic

[wiwbiz]

Is it true that any variable accepted as a char string and then scanned as int performs more quick mathematics operations such as pow() or log() function than a usual int input ?

[dargueta]

No, because to operate they all have to be converted to binary representation anyway. Besides, taking a string and converting it into an integer takes more time, so I'd say it's actually the opposite.

[wiwbiz]

TY for reply ( someone's listening ...)

Here's why I put this ;
There are 2 code for same problem:

#include<iostream>
using namespace std;
long long *arr = NULL;
long long findTotalProfit(long long num)
{
if((num < 1000000) && (arr[num] != 0))
return arr[num];
long long dividedProfit = findTotalProfit(num / 2) + findTotalProfit(num / 3) + findTotalProfit(num / 4);
//cout << dividedProfit << endl;
if(dividedProfit > num)
{
    if(num < 1000000)
    arr[num] = dividedProfit;
    return dividedProfit;
}
else
{
    if(num < 1000000)
    arr[num] = num;
    return num;
}
}
int main()
{
long long num;
arr = (long long *)malloc(10000000);
for(long long i = 1; i < 12; i++)
arr[i] = i;
char s[20];
while(cin.getline(s, 20))
{
sscanf(s, "%lld", &num);
long long ans = findTotalProfit(num);
printf("%lld\n", ans);
}
return 0;
}

2nd one:

// Bytelandian Gold Coins
#include<iostream>
#include<ctime>
using namespace std;
long long *arr=NULL;
long long sum(long long n)
{
if((n<100000) && (arr[n]!=0))
return arr[n];
long long m=sum(n/2)+sum(n/3)+sum(n/4);

if(m>n)
{
    if(n < 10000)
    arr[n] = m;
    return m;
}
else
{
    if(n < 10000)
    arr[n]=n;
    return n;}
}

int main()
{
long long n;
int t,u;
arr =(long long *)malloc(1000000);
for(int i=0;i<12;i++)
arr[i]=i;
while(cin>>n)
if(n!=0)cout<<sum(n);
else cout<<0<<endl;
return 0;
}

To elaborate, both program convert a given int to sum of its half, one-third and one-forth if it is greater than the int itself.The half and one third and one forth are again put under same constrain as the number to convert them before adding.

The former works much faster than the later. I doubted it for scanning string for int or use of malloc function. I haven't gone through malloc yet. Is something else the reason for faster run of this program ? Please response soon this time. You might have guessed correctly, the later one is my code.