tyvj 1432 楼兰图腾

Posted 2020-10-27 Mr_Wolfram的高维空间

树状数组

本题数据有误
对于每一个点用权值树状数组维护在这个点之后之前的比他大和比他小的数

#include <iostream>
#include <cstdio>
#include <string.h>
#include <algorithm>
#include <cmath>
#include <map>
#include <climits>
using namespace std;

#define lson rt<<1,l,mid
#define rson rt<<1|1,mid+1,r

typedef long long ll;
const int INF=0x3f3f3f3f;
const int maxn=2e5+10;
int T,n,m,k;
int a[maxn];
int sum[maxn<<2];

void PushUp(int rt){
    sum[rt]=sum[rt<<1]+sum[rt<<1|1];
}

void Update(int rt,int l,int r,int pos){
    if(l==r){
        sum[rt]++;
        return ;
    }
    int mid=(l+r)>>1;
    if(pos<=mid) Update(lson,pos);
    else Update(rson,pos);
    PushUp(rt);
}

ll Query(int rt,int l,int r,int L,int R){
    if(L<=l&&r<=R) return sum[rt];
    int mid=(l+r)>>1;
    ll ans=0;
    if(L<=mid) ans+=Query(lson,L,R);
    if(R>mid) ans+=Query(rson,L,R);
    return ans;
}

int main(){
#ifndef ONLINE_JUDGE
    freopen("test.in","r",stdin);
    freopen("test.out","w",stdout);
#endif
    while(~scanf("%d",&n)){
        for(int i=1;i<=n;i++) scanf("%d",&a[i]);
        memset(sum,0,sizeof(sum));
        ll ans1=0,ans2=0;
        for(int i=1;i<=n;i++){
            ll tmp1=Query(1,1,n,1,a[i]);
            ll tmp2=Query(1,1,n,a[i],n);
            ans1+=tmp2*(n-a[i]-tmp2);
            ans2+=tmp1*(a[i]-1-tmp1);
            Update(1,1,n,a[i]);
        }
        printf("%lld %lld\n",ans1,ans2);
    }
    return 0;
}