题解 | #等差数列#
等差数列
https://www.nowcoder.com/practice/f792cb014ed0474fb8f53389e7d9c07f
package main
import (
"fmt"
"bufio"
"os"
"strconv"
)
func main() {
input := bufio.NewScanner(os.Stdin)
input.Scan()
num, _ := strconv.Atoi(input.Text())
// 求出对应num位置的值
numByIndex := 2 + 3*(num-1)
// 对应的和
res := (2 + numByIndex) * num / 2
fmt.Println(res)
}
查看17道真题和解析