Golang 003. 分解阶乘的质因数
作者：互联网
【基础入门题】Golang 003. 分解阶乘的质因数
分解 n! 的质因数，写成连乘的样式，因数多于一个用^m表示个数。
如：Factor(6) = 2^4x3^2x5; Factor(8) = 2^7x3^2x5x7
方法一：
package main
import (
"fmt"
"strconv"
)
func Factorial(n int) int {
result := 1
for i := 1; i <= n; i++ {
result *= i
}
return result
}
func Factor(n int) string {
result := ""
n = Factorial(n)
for i := 2; i <= n; i++ {
count := 0
for n%i == 0 {
count++
n /= i
}
if count > 0 {
if count == 1 {
result += "x" + strconv.Itoa(i)
} else {
result += "x" + strconv.Itoa(i) + "^" + strconv.Itoa(count)
}
}
}
return result[1:]
}
func main() {
fmt.Printf("Factor(%d) = %s\n", 6, Factor(6))
fmt.Printf("Factor(%d) = %s\n", 8, Factor(8))
}
方法二：
package main
import (
"fmt"
"strconv"
)
func Factorial(n int) int {
result := 1
for i := 1; i <= n; i++ {
result *= i
}
return result
}
func Factor(n int) string {
result := ""
n = Factorial(n)
for i := 2; i <= n; i++ {
count := 0
for n%i == 0 {
count++
n /= i
if count == 1 {
result += "x" + strconv.Itoa(i)
}
}
if count > 1 {
result += "^" + strconv.Itoa(count)
}
}
return result[1:]
}
func main() {
fmt.Printf("Factor(%d) = %s\n", 6, Factor(6))
fmt.Printf("Factor(%d) = %s\n", 8, Factor(8))
fmt.Printf("Factor(%d) = %s\n", 10, Factor(10))
/* Out:
Factor(6) = 2^4x3^2x5
Factor(8) = 2^7x3^2x5x7
Factor(10) = 2^8x3^4x5^2x7
*/
}
方法三：【优化】合并阶乘函数、减少循环次数
package main
import (
"fmt"
"strconv"
)
func Factor(m int) string {
n := 1
for i := 1; i <= m; i++ {
n *= i
}
result := ""
for i := 2; i <= m; i++ {
count := 0
for n%i == 0 {
count++
n /= i
if count == 1 {
result += "x" + strconv.Itoa(i)
}
}
if count > 1 {
result += "^" + strconv.Itoa(count)
}
}
return result[1:]
}
func main() {
fmt.Printf("Factor(%d) = %s\n", 6, Factor(6))
fmt.Printf("Factor(%d) = %s\n", 8, Factor(8))
fmt.Printf("Factor(%d) = %s\n", 10, Factor(10))
/* Out:
Factor(6) = 2^4x3^2x5
Factor(8) = 2^7x3^2x5x7
Factor(10) = 2^8x3^4x5^2x7
*/
}方法四： 使用数组，追加后连接
package main
import (
"fmt"
"strconv"
"strings"
)
func Factor(m int) string {
n := 1
res := []string{}
for i := 1; i <= m; i++ {
n *= i
}
for i := 2; i <= m; i++ {
count := 0
for n%i == 0 {
count++
n /= i
}
if count == 1 {
res = append(res, strconv.Itoa(i))
} else if count > 1 {
res = append(res, strconv.Itoa(i)+"^"+strconv.Itoa(count))
}
}
return strings.Join(res, "x")
}
func main() {
fmt.Printf("Factor(%d) = %s\n", 6, Factor(6))
fmt.Printf("Factor(%d) = %s\n", 8, Factor(8))
fmt.Printf("Factor(%d) = %s\n", 10, Factor(10))
}
方法五：使用bytes.Buffer
package main
import (
"fmt"
"bytes"
"strconv"
)
func Factor(m int) string {
var n int = 1
var buf bytes.Buffer
for i := 1; i <= m; i++ {
n *= i
}
for i := 2; i <= m; i++ {
count := 0
for n%i == 0 {
count++
n /= i
if count == 1 {
buf.WriteString("x" + strconv.Itoa(i))
}
}
if count > 1 {
buf.WriteString("^" + strconv.Itoa(count))
}
}
result := buf.String()
return result[1:]
}
func main() {
fmt.Printf("Factor(%d) = %s\n", 6, Factor(6))
fmt.Printf("Factor(%d) = %s\n", 8, Factor(8))
fmt.Printf("Factor(%d) = %s\n", 10, Factor(10))
}
方法六：和方法五类似，使用strings.Builder
package main
import (
"fmt"
"strings"
"strconv"
)
func Factor(m int) string {
var n int = 1
var buf strings.Builder
for i := 1; i <= m; i++ {
n *= i
}
for i := 2; i <= m; i++ {
count := 0
for n%i == 0 {
count++
n /= i
if count == 1 {
buf.WriteString("x" + strconv.Itoa(i))
}
}
if count > 1 {
buf.WriteString("^" + strconv.Itoa(count))
}
}
result := buf.String()
return result[1:]
}
func main() {
fmt.Printf("Factor(%d) = %s\n", 6, Factor(6))
fmt.Printf("Factor(%d) = %s\n", 8, Factor(8))
fmt.Printf("Factor(%d) = %s\n", 10, Factor(10))
}
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标签：003,fmt,Factor,strconv,Golang,result,func,Printf,阶乘 来源： https://blog.csdn.net/boysoft2002/article/details/121647299