数组中最大的完美立方数
给定一组 N 个整数。任务是找出最大的数，也就是一个完美的立方体。如果没有完美立方体的数字，打印-1。 示例 :
Input : arr[] = {16, 8, 25, 2, 3, 10}
Output : 25
Explanation: 25 is the largest number
that is a perfect cube.
Input : arr[] = {36, 64, 10, 16, 29, 25|
Output : 64
一个简单的解决方案是对元素进行排序，并对 N 个数字进行排序，然后使用 cbrt()函数从后面开始检查一个完美的立方数。最后的第一个数字是一个完美的立方数，这就是我们的答案。排序的复杂度为 O(n log n)，cbrt()函数的复杂度为 log n，所以最坏的情况下复杂度为 O(n log n)。 一个高效解就是对 O(n)中的所有元素进行迭代，每次与最大元素进行比较，存储所有完美立方体的最大值。 以下是上述方法的实施:
C++
// CPP program to find the largest perfect
// cube number among n numbers
#include <bits/stdc++.h>
using namespace std;
// Function to check if a number
// is perfect cube number or not
bool checkPerfectcube(int n)
{
// takes the sqrt of the number
int d = cbrt(n);
// checks if it is a perfect
// cube number
if (d * d * d == n)
return true;
return false;
}
// Function to find the largest perfect
// cube number in the array
int largestPerfectcubeNumber(int a[], int n)
{
// stores the maximum of all
// perfect cube numbers
int maxi = -1;
// Traverse all elements in the array
for (int i = 0; i < n; i++) {
// store the maximum if current
// element is a perfect cube
if (checkPerfectcube(a[i]))
maxi = max(a[i], maxi);
}
return maxi;
}
// Driver Code
int main()
{
int a[] = { 16, 64, 25, 2, 3, 10 };
int n = sizeof(a) / sizeof(a[0]);
cout << largestPerfectcubeNumber(a, n);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find the largest perfect
// cube number among n numbers
class Solution
{
// Function to check if a number
// is perfect cube number or not
static boolean checkPerfectcube(int n)
{
// takes the sqrt of the number
int d =(int) Math.cbrt(n);
// checks if it is a perfect
// cube number
if (d * d * d == n)
return true;
return false;
}
// Function to find the largest perfect
// cube number in the array
static int largestPerfectcubeNumber(int a[], int n)
{
// stores the maximum of all
// perfect cube numbers
int maxi = -1;
// Traverse all elements in the array
for (int i = 0; i < n; i++) {
// store the maximum if current
// element is a perfect cube
if (checkPerfectcube(a[i]))
maxi = Math.max(a[i], maxi);
}
return maxi;
}
// Driver Code
public static void main(String args[])
{
int a[] = { 16, 64, 25, 2, 3, 10 };
int n =a.length;
System.out.print(largestPerfectcubeNumber(a, n));
}
}
//contributed by Arnab Kundu
Python 3
# Python 3 program to find the largest
# perfect cube number among n numbers
import math
# Function to check if a number
# is perfect cube number or not
def checkPerfectcube(n):
# checks if it is a perfect
# cube number
cube_root = n**(1./3.)
if round(cube_root) ** 3 == n:
return True
else:
return False
# Function to find the largest perfect
# cube number in the array
def largestPerfectcubeNumber(a, n):
# stores the maximum of all
# perfect cube numbers
maxi = -1
# Traverse all elements in the array
for i in range(0, n, 1):
# store the maximum if current
# element is a perfect cube
if (checkPerfectcube(a[i])):
maxi = max(a[i], maxi)
return maxi;
# Driver Code
if __name__ == '__main__':
a = [16, 64, 25, 2, 3, 10]
n = len(a)
print(largestPerfectcubeNumber(a, n))
# This code is contributed by
# Surendra_Gangwar
C
//C# program to find the largest perfect
// cube number among n numbers
using System;
public class Solution
{
// Function to check if a number
// is perfect cube number or not
static bool checkPerfectcube(int n)
{
// takes the sqrt of the number
int d = (int)Math.Ceiling(Math.Pow(n, (double)1 / 3));
// checks if it is a perfect
// cube number
if (d * d * d == n)
return true;
return false;
}
// Function to find the largest perfect
// cube number in the array
static int largestPerfectcubeNumber(int []a, int n)
{
// stores the maximum of all
// perfect cube numbers
int maxi = -1;
// Traverse all elements in the array
for (int i = 0; i < n; i++) {
// store the maximum if current
// element is a perfect cube
if (checkPerfectcube(a[i]))
maxi = Math.Max(a[i], maxi);
}
return maxi;
}
// Driver Code
public static void Main()
{
int []a = { 16, 64, 25, 2, 3, 10 };
int n =a.Length;
Console.WriteLine(largestPerfectcubeNumber(a, n));
}
}
/*This code is contributed by PrinciRaj1992*/
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to find the largest perfect
// cube number among n numbers
// Function to check if a number
// is perfect cube number or not
function checkPerfectcube($n)
{
// takes the sqrt of the number
$d = pow($n, (1 / 3));
$d = round($d);
// checks if it is a perfect
// cube number
if ($d * $d * $d == $n)
return true;
return false;
}
// Function to find the largest perfect
// cube number in the array
function largestPerfectcubeNumber(&$a, $n)
{
// stores the maximum of all
// perfect cube numbers
$maxi = -1;
// Traverse all elements in the array
for ($i = 0; $i < $n; $i++)
{
// store the maximum if current
// element is a perfect cube
if (checkPerfectcube($a[$i]))
$maxi = max($a[$i], $maxi);
}
return $maxi;
}
// Driver Code
$a = array( 16, 64, 25, 2, 3, 10 );
$n = sizeof($a);
echo largestPerfectcubeNumber($a, $n);
// This code is contributed by ita_c
?>
java 描述语言
<script>
// Javascript program to find the largest perfect
// cube number among n numbers
// Function to check if a number
// is perfect cube number or not
function checkPerfectcube(n)
{
// takes the sqrt of the number
let d = parseInt(Math.cbrt(n));
// checks if it is a perfect
// cube number
if (d * d * d == n)
return true;
return false;
}
// Function to find the largest perfect
// cube number in the array
function largestPerfectcubeNumber(a, n)
{
// stores the maximum of all
// perfect cube numbers
let maxi = -1;
// Traverse all elements in the array
for (let i = 0; i < n; i++) {
// store the maximum if current
// element is a perfect cube
if (checkPerfectcube(a[i]))
maxi = Math.max(a[i], maxi);
}
return maxi;
}
// Driver Code
let a = [ 16, 64, 25, 2, 3, 10 ];
let n = a.length;
document.write(largestPerfectcubeNumber(a, n));
</script>
Output:
64
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