unordered_multiset::load_factor()是C++ STL中的內置函數,該函數返回unordered_multiset容器中的當前負載係數。負載係數是容器中的元素數量(其大小)與鏟鬥數量(bucket_count)之比:
load_factor = size / bucket_count
負載因子會影響哈希表中發生衝突的概率(即,兩個元素位於同一存儲桶中的概率)。通過在每次需要擴展時進行重新哈希處理,容器會自動增加鏟鬥數,以將負載係數保持在特定閾值以下(其max_load_factor)。
用法:
unordered_multiset_name.load_factor
參數:該函數不接受任何參數。
返回值:該函數返回當前的負載係數。它可以是整數或雙精度類型。
以下示例程序旨在說明unordered_multiset::load_factor()函數:
程序1:
// C++ program to illustrate the
// unordered_multiset::load_factor() function
#include <bits/stdc++.h>
using namespace std;
int main()
{
// declaration
unordered_multiset<char> sample;
// inserts element
sample.insert('a');
sample.insert('b');
cout << "The size is: " << sample.size();
cout << "\nThe bucket_count is: " << sample.bucket_count();
cout << "\nThe load_factor is: " << sample.load_factor();
sample.insert('b');
sample.insert('b');
cout << "\n\nThe size is: " << sample.size();
cout << "\nThe bucket_count is: " << sample.bucket_count();
cout << "\nThe load_factor is: " << sample.load_factor();
sample.insert('z');
cout << "\n\nThe size is: " << sample.size();
cout << "\nThe bucket_count is: " << sample.bucket_count();
cout << "\nThe load_factor is: " << sample.load_factor();
return 0;
}
輸出:
The size is: 2 The bucket_count is: 3 The load_factor is: 0.666667 The size is: 4 The bucket_count is: 7 The load_factor is: 0.571429 The size is: 5 The bucket_count is: 7 The load_factor is: 0.714286
程序2:
// C++ program to illustrate the
// unordered_multiset::load_factor() function
#include <bits/stdc++.h>
using namespace std;
int main()
{
// declaration
unordered_multiset<int> sample;
// inserts element
sample.insert(1);
sample.insert(1);
cout << "The size is: " << sample.size();
cout << "\nThe bucket_count is: " << sample.bucket_count();
cout << "\nThe load_factor is: " << sample.load_factor();
sample.insert(1);
sample.insert(2);
cout << "\n\nThe size is: " << sample.size();
cout << "\nThe bucket_count is: " << sample.bucket_count();
cout << "\nThe load_factor is: " << sample.load_factor();
sample.insert(2);
cout << "\n\nThe size is: " << sample.size();
cout << "\nThe bucket_count is: " << sample.bucket_count();
cout << "\nThe load_factor is: " << sample.load_factor();
return 0;
}
輸出:
The size is: 2 The bucket_count is: 3 The load_factor is: 0.666667 The size is: 4 The bucket_count is: 7 The load_factor is: 0.571429 The size is: 5 The bucket_count is: 7 The load_factor is: 0.714286
相關用法
- C++ log()用法及代碼示例
- C++ div()用法及代碼示例
- C++ fma()用法及代碼示例
- C++ real()用法及代碼示例
- C++ map key_comp()用法及代碼示例
- C++ imag()用法及代碼示例
- C++ regex_iterator()用法及代碼示例
- C++ valarray tan()用法及代碼示例
- C++ valarray pow()用法及代碼示例
- C++ valarray sin()用法及代碼示例
注:本文由純淨天空篩選整理自gopaldave大神的英文原創作品 unordered_multiset load_factor() function in C++ STL。非經特殊聲明,原始代碼版權歸原作者所有,本譯文未經允許或授權,請勿轉載或複製。