dwrz/exercism
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Refactor c/difference-of-squares

Browse Source 
Curious to benchmark the different approaches.
This commit is contained in:
dwrz
2019-06-07 02:37:02 +00:00
parent f8127fdf4a
commit 61cea0dd0c
1 changed files with 8 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
c/difference-of-squares/src/difference_of_squares.c
+8 -7
View File
@@ -1,16 +1,17 @@
#include <stdio.h> #include <stdio.h>
// The sum of the first N natural numbers can be calculated as
// N * (N + 1) / 2. To get the square, we multiply the sum with itself.
// This formula saves us from having to loop up to N.
int square_of_sum(int n) { int square_of_sum(int n) {
int sum = (n * (n + 1)) / 2; return ((n * (n + 1)) / 2) * ((n * (n + 1)) / 2);
return sum * sum;
} }
// The sum of the squares of the first N natural numbers can be
// calculated as (n * (n + 1) * ((2 * n) + 1)) / 6.
// This formula saves us from having to loop up to N.
int sum_of_squares(int n) { int sum_of_squares(int n) {
int sum = 0; return (n * (n + 1) * ((2 * n) + 1)) / 6;
for (int i = 1; i <= n; i++) sum += i * i;
return sum;
} }
int difference_of_squares(int n) { int difference_of_squares(int n) {