Project Euler - 001
本帖最后由 icymirror 于 2015-09-26 17:34 编辑最近没有那么忙，开始学习golang，有空就拿Project Euler上的题目来练手吧。
Problem 1.
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
Find the sum of all the multiples of 3 or 5 below 1000.
问题1：
如果我们把10以内的3或5的倍数列出来，我们会得到：3, 5, 6和9。这些数之和是23。
现在，找出1000以内的3或5的倍数的数字之和。
method 1package main
import (
"fmt"
)
func Problem001_basic(scope, factor1, factor2 int) int {
sum := 0
for index := 0; index <= scope; index += factor1 {
sum = sum + index
}
for index := 0; index <= scope; index += factor2 {
sum = sum + index
}
for index := 0; index <= scope; index += factor1 * factor2 {
sum = sum - index
}
return sum
}
func Problem001_improve(scope, factor1, factor2 int) int {
sum := (factor1 + scope / factor1 * factor1) * (scope / factor1) / 2
sum = sum + (factor2 + scope / factor2 * factor2) * (scope / factor2) / 2
factor3 := factor1 * factor2
sum = sum -(factor3 + scope / factor3 * factor3) * (scope / factor3) / 2
return sum
}
func main() {
fmt.Println("Problem 001 result: ", Problem001_basic(1000, 3, 5))
fmt.Println("Problem 001 result: ", Problem001_improve(1000, 3, 5))
} 本帖最后由 ba_du_co 于 2015-10-09 14:45 编辑
拿来练练手。
233168#!perl6
say [+] (^1000).grep: * %% (3|5);
结果是 234168吧！回复 2# ba_du_co
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