# 数组中的最大值，至少是其他元素的两倍 > 原文： [https://www.geeksforgeeks.org/maximum-array-least-twice-elements/](https://www.geeksforgeeks.org/maximum-array-least-twice-elements/) 给定长度为 n 的整数数组。 我们的任务是返回 max 元素的索引，如果它的索引至少是数组中每个其他数字的两倍。 如果 max 元素不满足条件，则返回-1。 **示例**： ``` Input : arr = {3, 6, 1, 0} Output : 1 Here, 6 is the largest integer, and for every other number in the array x, 6 is more than twice as big as x. The index of value 6 is 1, so we return 1. Input : arr = {1, 2, 3, 4} Output : -1 4 isn't at least as big as twice the value of 3, so we return -1. ``` **方法**：扫描数组以查找唯一的最大元素 **m** ，并跟踪其索引 **maxIndex** 。 再次扫描数组。 如果我们发现 **x！= m** 与 **m < 2 * x** ，我们应该返回 **-1** 。 否则，我们应该返回 **maxIndex** 。 ## C++ ```cpp // CPP program for Maximum of // the array which is at least // twice of other elements of // the array. #include<bits/stdc++.h> using namespace std; // Function to find the  // index of Max element  // that satisfies the  // condition int findIndex(int arr[], int len) {      // Finding index of     // max of the array     int maxIndex = 0;     for (int i = 0; i < len; ++i)          if (arr[i] > arr[maxIndex])             maxIndex = i;     // Returns -1 if the     // max element is not      // twice of the i-th     // element.      for (int i = 0; i < len; ++i)                      if (maxIndex != i &&             arr[maxIndex] < 2 * arr[i])             return -1;     return maxIndex; } // Driver function int main(){     int arr[] = {3, 6, 1, 0};     int len = sizeof(arr) / sizeof(arr[0]);     cout<<(findIndex(arr, len)); } // This code is contributed by Smitha Dinesh Semwal ``` ## Java ```java // Java program for Maximum of the array // which is at least twice of other elements  // of the array. import java.util.*; import java.lang.*; class GfG {     // Function to find the index of Max element     // that satisfies the condition     public static int findIndex(int[] arr) {                 // Finding index of max of the array         int maxIndex = 0;         for (int i = 0; i < arr.length; ++i)              if (arr[i] > arr[maxIndex])                 maxIndex = i;         // Returns -1 if the max element is not          // twice of the i-th element.                 for (int i = 0; i < arr.length; ++i)                          if (maxIndex != i && arr[maxIndex] < 2 * arr[i])                 return -1;         return maxIndex;     }     // Driver function     public static void main(String argc[]){         int[] arr = new int[]{3, 6, 1, 0};         System.out.println(findIndex(arr));     } } ``` ## Python3 ```py # Python 3 program for Maximum of  # the array which is at least twice   # of other elements of the array. # Function to find the index of Max  # element that satisfies the condition def findIndex(arr):      # Finding index of max of the array     maxIndex = 0     for i in range(0,len(arr)):         if (arr[i] > arr[maxIndex]):             maxIndex = i     # Returns -1 if the max element is not      # twice of the i-th element.          for i in range(0,len(arr)):              if (maxIndex != i and                  arr[maxIndex] < (2 * arr[i])):             return -1     return maxIndex # Driver code arr = [3, 6, 1, 0] print(findIndex(arr)) # This code is contributed by Smitha Dinesh Semwal ``` ## C# ```cs // C# program for Maximum of the array // which is at least twice of other elements  // of the array. using System; class GfG {     // Function to find the index of Max element     // that satisfies the condition     public static int findIndex(int[] arr) {              // Finding index of max of the array         int maxIndex = 0;         for (int i = 0; i < arr.Length; ++i)              if (arr[i] > arr[maxIndex])                 maxIndex = i;         // Returns -1 if the max element is not          // twice of the i-th element.          for (int i = 0; i < arr.Length; ++i)                      if (maxIndex != i && arr[maxIndex] < 2 * arr[i])                 return -1;         return maxIndex;     }     // Driver function     public static void Main()     {         int[] arr = new int[]{3, 6, 1, 0};         Console.WriteLine(findIndex(arr));     } } // This code is contributed by vt_m. ``` ## PHP ```php <?php // PHP program for Maximum of // the array which is at least // twice of other elements of // the array. // Function to find the  // index of Max element  // that satisfies the  // condition function findIndex($arr, $len)  {      // Finding index of     // max of the array     $maxIndex = 0;     for ( $i = 0; $i < $len; ++$i)          if ($arr[$i] > $arr[$maxIndex])             $maxIndex = $i;     // Returns -1 if the     // max element is not      // twice of the i-th     // element.      for ($i = 0; $i < $len; ++$i)                      if ($maxIndex != $i and             $arr[$maxIndex] < 2 * $arr[$i])             return -1;     return $maxIndex; } // Driver Code $arr = array(3, 6, 1, 0); $len = count($arr); echo findIndex($arr, $len); // This code is contributed by anuj_67\. ?> ``` **输出**： ``` 1 ``` **时间复杂度**： * * * * * *