题解 | #求解立方根#

package main

import (
    "fmt"
    "math"
)

func main() {
    var input float64
    fmt.Scan(&input)
    
    if input == 0 || input == 1 || input == -1 {
        fmt.Printf("%.1f", input)
        return
    }
    
    var ne = input < 0
    if ne {
        input = input * -1
    }
    
    var small = input < 1
    
    var low, mid, high, triple float64
    if small {
        low = 0
        high = 1
    } else {
        low = 1
        high = input
    }
    
    for {
        mid = (low+high) / 2
        triple = mid*mid*mid
        if math.Abs(input - triple) < 0.01 {
            break
        } else if triple > input {
            high = mid
        } else if triple < input {
            low = mid
        }
    }
    
    if ne {
        mid *= -1
    }
    
    fmt.Printf("%.1f", mid)
}

// 本题输入一个浮点数，所以采用：fmt.Scan(&input)