1 #include
     
       2 #include
      
        3  4 int a[1000004],tmp1[500002],tmp2[500002]; 5 long long cnt; 6 void merge(int start,int mid,int end){ 7     int i,j,k; 8     for(k=0,i=start; i<=mid; i++) 9         tmp1[k++]=a[i];10     tmp1[k]=0x7fffffff;11     for(k=0,i=mid+1; i<=end; i++)12         tmp2[k++]=a[i];13     tmp2[k]=0x7fffffff;14     for(i=j=0,k=start; k<=end; k++){15         if(tmp1[i]<=tmp2[j]){16             a[k]=tmp1[i++];17         }else{18             a[k]=tmp2[j++];19             cnt+=mid-start+1-i; 20         }21     }22 }23 24 void mergeSort(int start,int end){25     if(start