# 数组元素的频率范围查询 > 原文： [https://www.geeksforgeeks.org/range-queries-for-frequencies-of-array-elements/](https://www.geeksforgeeks.org/range-queries-for-frequencies-of-array-elements/) 给定`n`个非负整数的数组。 任务是在`array[]`的任意范围内查找特定元素的频率。 范围以数组中的位置（不是基于 0 的索引）的形式给出。 可以有多个给定类型的查询。 **示例**： ``` Input : arr[] = {2, 8, 6, 9, 8, 6, 8, 2, 11}; left = 2, right = 8, element = 8 left = 2, right = 5, element = 6 Output : 3 1 The element 8 appears 3 times in arr[left-1..right-1] The element 6 appears 1 time in arr[left-1..right-1] ``` **朴素的方法**：是从左到右遍历并在找到元素时更新计数变量。 以下是朴素方法的代码：- ## C++ ```cpp // C++ program to find total count of an element // in a range #include<bits/stdc++.h> using namespace std; // Returns count of element in arr[left-1..right-1] int findFrequency(int arr[], int n, int left,                          int right, int element) {     int count = 0;     for (int i=left-1; i<=right; ++i)         if (arr[i] == element)             ++count;     return count; } // Driver Code int main() {     int arr[] = {2, 8, 6, 9, 8, 6, 8, 2, 11};     int n = sizeof(arr) / sizeof(arr[0]);     // Print frequency of 2 from position 1 to 6     cout << "Frequency of 2 from 1 to 6 = "          << findFrequency(arr, n, 1, 6, 2) << endl;     // Print frequency of 8 from position 4 to 9     cout << "Frequency of 8 from 4 to 9 = "          << findFrequency(arr, n, 4, 9, 8);     return 0; } ```