## 10268 - 498-bis

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### 10268 - 498-bis

Getting WA...plzz help
Code: Select all
`#include<cstdio>#include<cstdlib>#include<cmath>#include<cstring>#include<iostream>#include<algorithm>#include<string>#include<sstream>using namespace std;int arr[100000000];            main(){      string strx,str;      while(getline(cin, strx))      {            stringstream ss(strx);            long long int x;            ss>>x;            getline(cin, str);            stringstream in(str);            int n = 0;            while(in >> arr[n])                n++;            long long int poly = 0;            for(int i = 0;i<n ; i++)                    poly = poly + (n-i-1)*arr[i]*pow(x,n-i-2.0);            printf("%lld\n", poly);      }}`
-@ce

@ce
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Posts: 66
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Location: Ranchi, India

### Re: 10268 - 498-bis

pow() returns a double and could lead to precision errors.
brianfry713
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Posts: 1861
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### Re: 10268 - 498-bis

Removing pow() gives TLE

Code: Select all
`#include<cstdio>#include<cstdlib>#include<cmath>#include<cstring>#include<iostream>#include<algorithm>#include<string>#include<sstream>using namespace std;int arr[100000000];long long int power(long long int x, long long int n){     if(n == 1)          return x;     else if(n == 0)          return 1;     else if(n&1)            return power(x,n/2)*power(x,n/2+1);     else            return power(x,n/2)*power(x,n/2);}main(){      string strx,str;      while(getline(cin, strx))      {            stringstream ss(strx);            long long int x;            ss>>x;            getline(cin, str);            stringstream in(str);            int n = 0;            while(in >> arr[n])                n++;            long long int poly = 0;            for(int i = 0;i<n ; i++)                    poly = poly + (n-i-1)*arr[i]*power(x,n-i-2);            printf("%lld\n", poly);      }}`
-@ce

@ce
Learning poster

Posts: 66
Joined: Mon May 28, 2012 8:46 am
Location: Ranchi, India

### Re: 10268 - 498-bis

brianfry713
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Posts: 1861
Joined: Thu Sep 01, 2011 9:09 am
Location: San Jose, CA, USA