本文实例讲述了C++求逆序对的方法，分享给大家供大家参考之用。具体实现方法如下：
#include <iostream> #include <vector> using namespace std; int array[] = {3, 9, 7, 4, 5, 2}; const int size = sizeof array / sizeof *array; int temp[size]; //int numbers[size]; int reversePair(int *numbers, int start, int last, int &index, int &count) { if(start == last) return 0; int mid = (last - start) / 2 + start; reversePair(numbers, start, mid, index, count); reversePair(numbers, mid + 1, last, index, count); for(int i = start; i <= last; i++) temp[i] = numbers[i]; int index1 = start, index2 = mid + 1; index = start; while(index1 <= mid && index2 <= last) { if(temp[index1] > temp[index2]) { numbers[index] = temp[index2]; count += mid - index1 + 1; index++; index2++; } else if(temp[index1] == temp[index2]) { numbers[index] = temp[index1]; index++; index1++; index2++; } else if(temp[index1] < temp[index2]) { numbers[index] = temp[index1]; index++; index1++; } } if(index1 <= mid) { while(index1 <= mid) { numbers[index] = temp[index1]; index++; index1++; } } else { while(index2 <= last) { numbers[index] = temp[index2]; index++; index2++; } } return count; } void main() { int count = 0; int index = 0; reversePair(array, 0, size - 1, index, count); cout << "count = " << count << endl; }
希望本文所述对大家C++算法设计的学习有所帮助。
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