题目链接

\(Description\)

有一片n亩的土地,要在这上面种草。

在每一亩土地上都种植了一种独一无二的草,其中,第\(i\)亩土地的草每天会长高\(a[i]\)厘米。

一共会进行\(m\)次收割,其中第\(i\)次收割在第\(d[i]\)天,并把所有高度大于等于\(b[i]\)的部分全部割去。求每次收割得到的草的高度总和是多少。

BZOJ.4293.[PA2015]Siano(线段树)-LMLPHP

/*
无论怎么收割,长得快的草一定是不矮于长得慢的;而询问与下标无关
所以按生长速度排序,某一时刻的高度一定是递增的,这样就可以二分了
注意很多longlong
小于x直接输出0!
Reset在查询里!所以查询中要有PushUp!
*/
#include<cstdio>
#include<cctype>
#include<algorithm>
#define gc() getchar()
#define now node[rt]
#define lson node[node[rt].ls]
#define rson node[node[rt].rs]
typedef long long LL;
const int N=5e5+5; LL A[N],sum[N];
struct Seg_Tree
{
int tot;
struct Node
{
LL maxn,sum,tag/*num of days*/,flag/*reset(>=0) or not(-1)*/;
int l,r,ls,rs;
Node() {flag=-1;}
}node[N<<1];
inline void PushUp(int rt)
{
now.sum = lson.sum + rson.sum;
now.maxn = rson.maxn;
// now.maxn = std::max(lson.maxn, rson.maxn);
}
inline void Reset(int rt,LL f)
{
now.sum=1LL*(now.r-now.l+1)*f, now.maxn=f;
now.tag=0, now.flag=f;
}
inline void Update(int rt,LL tg)
{
now.tag += tg;
now.sum += (sum[now.r]-sum[now.l-1])*tg;
now.maxn += A[now.r]*tg;//最大值肯定是最高的那个
}
void PushDown(int rt)
{
if(~now.flag)
{
Reset(now.ls,now.flag), Reset(now.rs,now.flag),
now.flag=-1;
}
if(now.tag)//reset后重新赋上的tag
{
Update(now.ls,now.tag), Update(now.rs,now.tag),
now.tag=0;
}
}
void Build(int l,int r)
{
int p=tot++;
node[p].l=l, node[p].r=r;
// node[p].tag=0, node[p].flag=-1;
if(l==r) ;
// node[p].ls = node[p].rs = -1,
// node[p].maxn = node[p].sum = A[l];
else
{
int m=l+r>>1;
node[p].ls=tot, Build(l,m);
node[p].rs=tot, Build(m+1,r);
// PushUp(p);
}
}
int Find(int rt,LL x)
{
if(now.l==now.r) return now.l;
PushDown(rt);
if(lson.maxn>=x) return Find(now.ls,x);
return Find(now.rs,x);
}
LL Query_Sum(int rt,int L,int R,LL x)//Reset N[L~R] to x
{
LL res=0;
if(L<=now.l && now.r<=R) {res=now.sum; Reset(rt,x); return res;}//!
PushDown(rt);
int m=now.l+now.r>>1;
if(L<=m) res=Query_Sum(now.ls,L,R,x);
if(m<R) res+=Query_Sum(now.rs,L,R,x);
PushUp(rt);//!
return res;
}
// LL Query_Sum(int rt,int p,LL x)//Reset N[L~R] to x
// {
// if(now.r < p) return 0;
// LL res;
// if(now.l >= p) {res=now.sum; Reset(rt,x); return res;}//!
// PushDown(rt);
// res=Query_Sum(now.ls,p,x)+Query_Sum(now.rs,p,x);
// PushUp(rt);
// return res;
// }
}t;
#undef now
inline LL read()
{
LL now=0;register char c=gc();
for(;!isdigit(c);c=gc());
for(;isdigit(c);now=now*10+c-'0',c=gc());
return now;
} int main()
{
#ifndef ONLINE_JUDGE
freopen("4293.in","r",stdin);
#endif LL n=read(),m=read();
for(int i=1; i<=n; ++i) A[i]=read();
std::sort(A+1,A+1+n);
t.Build(1,n);
for(int i=1; i<=n; ++i) sum[i]=sum[i-1]+A[i];
for(LL res,day,x,las=0,pos; m; --m,las=day)
{
day=read(),x=read();
t.Update(0, day-las);
if(t.node[0].maxn < x) {puts("0"); continue;}//很有效 and必须要加!
pos=t.Find(0,x), printf("%lld\n",t.Query_Sum(0,pos,n,x)-(n-pos+1)*x);//longlong
// pos=t.Find(0,x), printf("%lld\n",t.Query_Sum(0,pos,x)-(n-pos+1)*x);//longlong
}
return 0;
}
05-07 15:34