目前最火最热门的python经典编程题之3

链接：https://www.nowcoder.com/questionTerminal/96bd6684e04a44eb80e6a68efc0ec6c5 来源：牛客网 public class Solution {     public int InversePairs(int [] array) {         if(array==null||array.length==0)         {             return 0;         }         int[] copy = new int[array.length];         for(int i=0;i<array.length;i++)         {             copy[i] = array[i];         }         int count = InversePairsCore(array,copy,0,array.length-1);//数值过大求余         return count;               }     private int InversePairsCore(int[] array,int[] copy,int low,int high)     {         if(low==high)         {             return 0;         }         int mid = (low+high)>>1;         int leftCount = InversePairsCore(array,copy,low,mid)%1000000007;         int rightCount = InversePairsCore(array,copy,mid+1,high)%1000000007;         int count = 0;         int i=mid;         int j=high;         int locCopy = high;         while(i>=low&&j>mid)         {             if(array[i]>array[j])             {                 count += j-mid;                 copy[locCopy--] = array[i--];                 if(count>=1000000007)//数值过大求余                 {                     count%=1000000007;                 }             }             else             {                 copy[locCopy--] = array[j--];             }         }         for(;i>=low;i--)         {             copy[locCopy--]=array[i];         }         for(;j>mid;j--)         {             copy[locCopy--]=array[j];         }         for(int s=low;s<=high;s++)         {             array[s] = copy[s];         }         return (leftCount+rightCount+count)%1000000007;     } }