【Luogu1973】仓配置

题面

直接找洛谷把。。。

题解

很明显的贪心吧
按照线段的右端点为第一关键字，左端点第二关键字排序
然后线段树维护区间最小就可以啦

#include<iostream>#include<cstdio>#include<cstdlib>#include<cstring>#include<cmath>#include<algorithm>#include<set>#include<map>#include<vector>using namespace std;#define MAX 110000#define lson (now<<1)#define rson (now<<1|1)inline int read(){    int x=0,t=1;char ch=getchar();    while((ch<'0'||ch>'9')&&ch!='-')ch=getchar();    if(ch=='-')t=-1,ch=getchar();    while(ch<='9'&&ch>='0')x=x*10+ch-48,ch=getchar();    return x*t;}int t[MAX<<2];int ly[MAX<<2];int N,M,a[MAX];void pushdown(int now){    int lyy=ly[now];    t[lson]-=lyy;t[rson]-=lyy;    ly[lson]+=lyy;ly[rson]+=lyy;    ly[now]=0;}void putlazy(int now){    t[now]--;ly[now]++;}void build(int now,int l,int r){    if(l==r){t[now]=a[l];return;}    int mid=(l+r)>>1;    build(lson,l,mid);build(rson,mid+1,r);    t[now]=min(t[lson],t[rson]);}int Query(int now,int l,int r,int al,int ar){    if(l==al&&r==ar)return t[now];    if(ly[now])pushdown(now);    int mid=(l+r)>>1;    if(ar<=mid)return Query(lson,l,mid,al,ar);    else if(al>mid)return Query(rson,mid+1,r,al,ar);    else return min(Query(lson,l,mid,al,mid),Query(rson,mid+1,r,mid+1,ar));}void Modify(int now,int l,int r,int al,int ar){    if(l==al&&r==ar){putlazy(now);return;}    int mid=(l+r)>>1;    if(ly[now])pushdown(now);    if(ar<=mid)Modify(lson,l,mid,al,ar);    else if(al>mid)Modify(rson,mid+1,r,al,ar);    else {Modify(lson,l,mid,al,mid);Modify(rson,mid+1,r,mid+1,ar);}    t[now]=min(t[lson],t[rson]);}struct Link{    int l,r;}gg[MAX];inline bool operator <(Link a,Link b){    if(a.r!=b.r)return a.r<b.r;    return a.l>b.r;}int main(){    N=read();M=read();    for(int i=1;i<=N;++i)a[i]=read();    for(int i=1;i<=M;++i)gg[i].l=read(),gg[i].r=read();    sort(&gg[1],&gg[M+1]);    build(1,1,N);    int ans=0;    for(int i=1;i<=M;++i)    {        int dd=Query(1,1,N,gg[i].l,gg[i].r);        if(!dd)continue;        ++ans;        Modify(1,1,N,gg[i].l,gg[i].r);    }    cout<<ans<<endl;    return 0;}