OpenSoure_Repos/TheAlgorithms-C-Plus-Plus
1
0
Fork 0
mirror of https://hub.njuu.cf/TheAlgorithms/C-Plus-Plus.git synced 2023-10-11 13:05:55 +08:00
Code Issues Packages Projects Releases Wiki Activity

Update math/lcm_sum.cpp

Browse Source 
Co-authored-by: David Leal <halfpacho@gmail.com>
This commit is contained in:
chestamittal 2020-10-20 03:03:12 +05:30 committed by chestamittal
parent 1ebb42185f
commit c7912e7b1b
1 changed files with 31 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

57
math/lcm_sum.cpp
View File

@ -13,41 +13,46 @@
#include <vector> /// for std::vector
/**
* Function to compute sum of euler totients in sumOfEulerTotient vector
* @param num input number
* @returns int Sum of LCMs, i.e. ∑LCM(i, num) from i = 1 to num
* @namespace math
* @brief Mathematical algorithms
*/
int lcmSum(int num) {
namespace math {
/**
* Function to compute sum of euler totients in sumOfEulerTotient vector
* @param num input number
* @returns int Sum of LCMs, i.e. ∑LCM(i, num) from i = 1 to num
*/
int lcmSum(int num) {
int i=0, j=0;
int limit = 1000;
std::vector <int> eulerTotient(limit);
std::vector <int> sumOfEulerTotient(limit);
int i=0, j=0;
int limit = 1000;
std::vector <int> eulerTotient(limit);
std::vector <int> sumOfEulerTotient(limit);
// storing initial values in eulerTotient vector
for(i=1; i<=limit; i++) {
eulerTotient[i] = i;
}
// storing initial values in eulerTotient vector
for(i=1; i<=limit; i++) {
eulerTotient[i] = i;
}
// applying totient sieve
for(i=2; i<=limit; i++) {
if(eulerTotient[i] == i) {
for(j=i; j<=limit; j+=i) {
eulerTotient[j] = eulerTotient[j]/i;
eulerTotient[j] = eulerTotient[j]*(i-1);
// applying totient sieve
for(i=2; i<=limit; i++) {
if(eulerTotient[i] == i) {
for(j=i; j<=limit; j+=i) {
eulerTotient[j] = eulerTotient[j]/i;
eulerTotient[j] = eulerTotient[j]*(i-1);
}
}
}
}
// computing sum of euler totients
for(i=1; i<=limit; i++) {
for(j=i; j <=limit; j+=i) {
sumOfEulerTotient[j] += eulerTotient[i]*i;
// computing sum of euler totients
for(i=1; i<=limit; i++) {
for(j=i; j <=limit; j+=i) {
sumOfEulerTotient[j] += eulerTotient[i]*i;
}
}
return ((sumOfEulerTotient[num] + 1 ) * num) / 2;
}
return ((sumOfEulerTotient[num] + 1 ) * num) / 2;
}
} // namespace math
/**