C++ 程序来计算数组中的反序
计数反序是指使数组有序所需的交换次数。反序计数 = 0,当数组有序时。反序计数 = 最大值,当数组按逆序排序时。
让我们开发一个 C++ 程序来计算数组中的反序。
算法
Begin Function CountInversionArray has arguments a[], n = number of elements. initialize counter c := 0 for i in range 0 to n-1, do for j in range (i + 1) to n, do if a[i] > a[j], then increase the count by 1 done done End.
示例代码
#include<iostream> using namespace std; int CountInversionArray(int a[], int n) { int i, j, c = 0; for(i = 0; i < n; i++) { for(j = i+1; j < n; j++) if(a[i] > a[j]) c++; } return c; } int main() { int n, i; cout<<"\nEnter the number of elements: "; cin>>n; int a[n]; for(i = 0; i < n; i++) { cout<<"Enter element "<<i+1<<": "; cin>>a[i]; } cout<<"\nThe number of inversion in the array: "<<CountInversionArray(a, n); return 0; }
输出
Enter the number of elements: 5 Enter element 1: 3 Enter element 2: 2 Enter element 3: 7 Enter element 4: 6 Enter element 5: 1 The number of inversion in the array: 6
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