康拓展开-----两个排列的位置之差

Posted 2020-08-09 请叫我凯凯大人

#include <iostream>
#include <cstring>
#include <cstdio>
#define LL long long
using namespace std;
const int maxn=105;
const int mod=1e6+7;

int T,n,a[maxn],b[maxn];
LL fac[maxn];
int vis[maxn];

void set(int high)
{
    fac[0]=1;
    for(int i=1;i<=high;i++)
        fac[i]=(fac[i-1]*i)%mod;
}

void deal(int a[],LL &ans)
{
    ans=0;
    memset(vis,0,sizeof(vis));
    for(int i=0;i<n;i++)
    {
        int cnt=0;
        for(int j=1;j<a[i];j++) if(!vis[j]) cnt++;
        ans=(ans+((cnt*fac[n-i-1])%mod))%mod;
        vis[a[i]]=1;
    }
}
int main()
{
    set(100);
    int Case=1;
    cin>>T;
    while(T--)
    {
        cin>>n;
        for(int i=0;i<n;i++) cin>>a[i];
        for(int i=0;i<n;i++) cin>>b[i];
        LL p1=0,p2=0,ans=0;
        deal(a,p1);deal(b,p2);

        int i=0;
        for(i=0;i<n;i++) if(a[i]!=b[i]) break;
        if(a[i]>b[i]) ans=(p1-p2)%mod;
        else ans=(p2-p1)%mod;
        cout<<"Case $"<<Case++<<":"<<endl<<(ans+mod)%mod<<endl;
    }
    return 0;
}


#include <iostream>
#include <cstring>
#include <cstdio>
#define LL long long
using namespace std;
const int maxn=105;
const int mod=1e6+7;

int T,n,a[maxn],b[maxn];
LL fac[maxn];
int vis[maxn];

void set(int high)
{
    fac[0]=1;
    for(int i=1;i<=high;i++)
        fac[i]=(fac[i-1]*i)%mod;
}

void deal(int a[],LL &ans)
{
    ans=0;
    memset(vis,0,sizeof(vis));
    for(int i=0;i<n;i++)
    {
        int cnt=0;
        for(int j=1;j<a[i];j++) if(!vis[j]) cnt++;
        ans=(ans+((cnt*fac[n-i-1])%mod))%mod;
        vis[a[i]]=1;
    }
}
int main()
{
    set(100);
    int Case=1;
    cin>>T;
    while(T--)
    {
        cin>>n;
        for(int i=0;i<n;i++) cin>>a[i];
        for(int i=0;i<n;i++) cin>>b[i];
        LL p1=0,p2=0,ans=0;
        deal(a,p1);deal(b,p2);

        int i=0;
        for(i=0;i<n;i++) if(a[i]!=b[i]) break;
        if(a[i]>b[i]) ans=(p1-p2)%mod;
        else ans=(p2-p1)%mod;
        cout<<"Case $"<<Case++<<":"<<endl<<(ans+mod)%mod<<endl;
    }
    return 0;
}