#include <iostream>using namespace std;int inversePairs(int *data, int *buf, int l, int r){    if (l >= r) return 0;    //初始化需要的变量,p1指向左子数组的最右，p2指向右子数组的最右    int count = 0;    int mid = (l + r) / 2;    int p1 = mid;    int p2 = r;    int lPairs = inversePairs(data, buf, l, mid);    int rPairs = inversePairs(data, buf, mid + 1, r);    int length = r - l + 1;    //数据复制到辅助数组    for (int curr = l; curr <= r; curr ++){        buf[curr] = data[curr];    }    //归并并且排序，注意讨论分支出现的顺序，避免数组操作出界    for (int curr = r; curr >= l; curr--){        if (p1<l){            data[curr] = buf[p2--];        }else{            if (p2 < mid + 1){                data[curr] = buf[p1--];            }else{                if (buf[p1] > buf[p2]){                data[curr] = buf[p1--];                count += (p2 - mid);                }else{                    data[curr] = buf[p2--];                }            }                    }    }    return (lPairs + rPairs + count);}int main(){#if 0    int data[4] = {7,5,6,4};    int temp[4] = { 0 };    int myCount = inversePairs(data, temp, 0, 3);    for (int i = 0; i < 4; i++)        cout << data[i]<<‘\t‘;    cout << endl;    cout << myCount;#endif    const int num = 6;    int data[num] = { 6, 2, 3, 6, 5, 0 };    int temp[num] = { 0 };    int myCount = inversePairs(data, temp, 0, 5);    for (int i = 0; i < num; i++)       cout << data[i] << ‘\t‘;    cout << endl;    cout << myCount;    system("pause");}