hdu 4325 树状数组+离散化

思路：这题的思路很容易想到，把所有时间点离散化，然后按时间一步一步来，当到达时间i的时候处理所有在i处的查询。

这个代码怎一个挫字了得

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#define Maxn 100010
#define lowbit(x) (x&(-x))
using namespace std;
int C[Maxn*],n,ans[Maxn];
struct Flower{
    int l,r;
}flower[Maxn];
struct Lisan{
    int val,type,l;
    int pos;
    int operator <(const Lisan &temp) const
    {
        return val<temp.val;
    }
}Index[Maxn*];
struct QT{
    int val,i;
    int operator <(const QT &temp) const
    {
        return val<temp.val;
    }
}qt[Maxn];
int Sum(int pos)
{
    int sum=;
    while(pos)
    {
        sum+=C[pos];
        pos-=lowbit(pos);
    }
    return sum;
}
void update(int pos,int val)
{
    while(pos<=n)
    {
        C[pos]+=val;
        pos+=lowbit(pos);
    }
}
vector<int> q[Maxn*];
int main()
{
    int i,j,m,t,Case=;
    scanf("%d",&t);
    while(t--)
    {
        memset(C,,sizeof(C));
        scanf("%d%d",&n,&m);
        int cnt=;
        for(i=;i<=n;i++)
        {
            scanf("%d%d",&flower[i].l,&flower[i].r);
            Index[++cnt].val=flower[i].l,Index[cnt].pos=i,Index[cnt].type=,Index[cnt].l=,Index[++cnt].val=flower[i].r,Index[cnt].type=,Index[cnt].pos=i,Index[cnt].l=;
        }
        for(i=;i<=m;i++)
        {
            scanf("%d",&qt[i].val);
            qt[i].i=i;
            Index[++cnt].val=qt[i].val;
            Index[cnt].type=;
            Index[cnt].pos=i;
        }
        sort(Index+,Index++cnt);
        //cout<<"ok"<<endl;
        int num=;
        if(Index[].type==)
        {
            qt[Index[].pos].val=++num;
        }
        else
        {
            if(Index[].l)
                flower[Index[].pos].l=++num;
            else
                flower[Index[].pos].r=++num;
        }
        for(i=;i<=cnt;i++)
        {
            if(Index[i].val>Index[i-].val)
            {
                if(Index[i].type==)
                {
                    qt[Index[i].pos].val=++num;
                }
                else
                {
                    if(Index[i].l)
                        flower[Index[i].pos].l=++num;
                    else
                        flower[Index[i].pos].r=++num;
                }
            }
            else
                if(Index[i].type==)
                {
                    qt[Index[i].pos].val=num;
                }
                else
                {
                    if(Index[i].l)
                        flower[Index[i].pos].l=num;
                    else
                        flower[Index[i].pos].r=num;
                }
        }
        for(i=;i<=num;i++)
            q[i].clear();
        for(i=;i<=n;i++)
        {
            q[flower[i].l].push_back();
            q[flower[i].r].push_back(-);
        }
        sort(qt+,qt+m+);
        int r=;
        n=num+;
        for(i=;i<=num;i++)
        {
            cnt=;
            if(r>m) break;
            int size=q[i].size();
            for(j=;j<size;j++)
            {
                update(i,q[i][j]);
                if(q[i][j]<)
                    cnt++;
            }
            while(qt[r].val==i&&r<=m)
            {
                ans[qt[r].i]=Sum(qt[r].val)+cnt;
                r++;
            }
        }
        printf("Case #%d:\n",++Case);
        for(i=;i<=m;i++)
            printf("%d\n",ans[i]);
    }
    return ;
}

这个代码就简洁多了：

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#define Maxn 100010
#define lowbit(x) (x&(-x))
using namespace std;
int C[Maxn*],n,Index[Maxn*];
struct Node{
    int val,pos;
    int operator <(const Node &temp) const
    {
        return val<temp.val;
    }
}node[Maxn*];
int Sum(int pos)
{
    int sum=;
    while(pos)
    {
        sum+=C[pos];
        pos-=lowbit(pos);
    }
    return sum;
}
void update(int pos,int val)
{
    while(pos<=n)
    {
        C[pos]+=val;
        pos+=lowbit(pos);
    }
}
int main()
{
    int t,m,i,j,Case=;
    scanf("%d",&t);
    while(t--)
    {
        memset(C,,sizeof(C));
        scanf("%d%d",&n,&m);
        int nx=n<<;
        int mx=nx+m;
        for(i=;i<=mx;i++)
        {
            scanf("%d",&node[i].val);
            node[i].pos=i;
        }
        sort(node+,node+mx+);
        int cnt=;
        Index[node[].pos]=++cnt;
        for(i=;i<=mx;i++)
        {
            if(node[i].val==node[i-].val)
                Index[node[i].pos]=cnt;
            else
                Index[node[i].pos]=++cnt;
        }
        n=cnt+;
        for(i=;i<=nx;i++)
        {
            //cout<<Index[i]<<" * ";
            update(Index[i++],);
            update(Index[i]+,-);
           // cout<<Index[i]+1<<endl;
        }
        printf("Case #%d:\n",++Case);
        for(i=nx+;i<=mx;i++)
        {
           // cout<<Index[i]<<endl;
            printf("%d\n",Sum(Index[i]));
        }
    }
    return ;
}