UVALive 6508 Permutation Graphs

Permutation Graphs

Time Limit:3000MS     Memory Limit:0KB     64bit IO Format:%lld & %llu

Submit Status Practice UVALive 6508

#include<stdio.h>
#include<string.h>

int temp[100005],a[100005],b[100005],c[100005],b1[100005];
long long num;

void merg_sort(int a[],int l,int r)
{
    int  i,j,len=r-l,p1,p2;
    if(len<=1)
        return;
    int mid=l+len/2;
    merg_sort(a,l,mid);
    merg_sort(a,mid,r);
    p1=l,p2=mid;
    for(i=l;i<r;i++)
    {
        if(p1==mid)
        {
            temp[i]=a[p2];
            p2++;
        }
        else if(p2==r)
        {
            temp[i]=a[p1];
            p1++;
        }
        else
        {
            if(a[p1]<=a[p2])
            {
                temp[i]=a[p1];
                p1++;
            }
            else
            {
                temp[i]=a[p2];
                p2++;
                num=num+mid-p1;
            }
        }
    }
    for(i=l;i<r;i++)
        a[i]=temp[i];
    return;
}

int main()
{
    int T;
    int n,i,j,k;
    scanf("%d",&T);
    while(T--)
    {
        num=0;
        scanf("%d",&n);
        for(i=1;i<=n;i++)
            scanf("%d",&b[i]);
        for(i=1;i<=n;i++)
            b1[b[i]]=i;

        for(i=1;i<=n;i++)
            scanf("%d",&c[i]);
        for(i=1;i<=n;i++)
            a[i]=b1[c[i]];

        /*for(i=1;i<=n;i++)
            printf("%d ",a[i]);*/
        merg_sort(a,1,n+1);
        printf("%lld
",num);
    }
    return 0;
}