bzoj2141: 排队 cdq分治

#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define repp(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
#define see(x) (cerr<<(#x)<<‘=‘<<(x)<<endl)
#define inf 0x3f3f3f3f
#define CLR(A,v)  memset(A,v,sizeof A)
///////////////////////////////////////
const int N=1e5+10;
int n,m,t[N+200],cnt,a[N],b[N];
ll ans[N];
void add(int x,int v){for(;x<=N+100;x+=x&-x)t[x]+=v;}
int qsum(int x){int ans=0;for(;x;x-=x&-x)ans+=t[x];return ans;}
struct node{int x,y,w,id;}s[N];
bool cmp(node a,node b){return a.x<b.x;}

void cdq(int l,int r)
{
    if(l==r)return ;int mid=(l+r)>>1;
    cdq(l,mid);cdq(mid+1,r);
    sort(s+l,s+mid+1,cmp);sort(s+mid+1,s+r+1,cmp);
    int j=l;
    rep(i,mid+1,r)
    {
        while(j<=mid&&s[j].x<=s[i].x)add(s[j].y,s[j].w),j++;
        ans[s[i].id]+=1ll*s[i].w*(qsum(N)-qsum(s[i].y));
    }
    while(--j>=l)add(s[j].y,-s[j].w);
    j=mid;
    repp(i,r,mid+1)
    {
        while(j>=l&&s[j].x>=s[i].x)add(s[j].y,s[j].w),j--;;
        ans[s[i].id]+=1ll*s[i].w*qsum(s[i].y-1);
    }
    while(++j<=mid)add(s[j].y,-s[j].w);
}
int main()
{
    cin>>n;
    rep(i,1,n)
    {
        int x;scanf("%d",&x);a[i]=b[i]=x;
        s[++cnt]=(node){i,x,1,0};
    }
    sort(b+1,b+1+n);
    int nn=unique(b+1,b+1+n)-b-1;
    rep(i,1,n)a[i]=lower_bound(b+1,b+1+nn,a[i])-b,
    s[i].y=lower_bound(b+1,b+1+nn,s[i].y)-b;
    cin>>m;
    rep(i,1,m)
    {
        int x,y;scanf("%d%d",&x,&y);
        s[++cnt]=(node){x,a[y],1,i};
        s[++cnt]=(node){y,a[x],1,i};
        s[++cnt]=(node){x,a[x],-1,i};
        s[++cnt]=(node){y,a[y],-1,i};
        swap(a[x],a[y]);
    }
    cdq(1,cnt);
    rep(i,1,m)
    ans[i]+=ans[i-1];
    rep(i,0,m)printf("%lld\n",ans[i]);
    return 0;
}