小恐 @ 2020-05-25 09:22:54
RT,除了第1个点其他全WA
#include<stdio.h>
#include<algorithm>
using namespace std;
const int NR=5e5+5;
const int MR=1e5+5;
const int INF=0x3f3f3f3f;
typedef long long LL;
int read()
{
int x=0;
int bei=1;
char ch=getchar();
while(ch<'0'||ch>'9')
{
if(ch=='-')
bei=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9')
{
x=x*10+ch-'0';
ch=getchar();
}
return x*=bei;
}
int a[NR];
struct Segtree
{
int sum,qian,hou,zong;
}segtree[NR<<2];
void build(int x,int l,int r)
{
if(l==r)
{
segtree[x]=(Segtree){a[l],a[l],a[l],a[l]};
return;
}
int ls=x<<1,rs=x<<1|1;
int mid=l+r>>1;
build(ls,l,mid);
build(rs,mid+1,r);
segtree[x].sum=segtree[ls].sum+segtree[rs].sum;
segtree[x].zong=max(segtree[ls].hou+segtree[rs].qian,max(segtree[ls].zong,segtree[rs].zong));
segtree[x].qian=max(segtree[ls].sum+segtree[rs].qian,segtree[ls].qian);
segtree[x].hou=max(segtree[rs].sum+segtree[ls].hou,segtree[rs].hou);
}
int lst;
int ans;
void query(int x,int l,int r,int nl,int nr)
{
if(nl<=l&&r<=nr)
{
ans=max(ans,max(lst+segtree[x].qian,segtree[x].zong));
lst=segtree[x].hou;
return;
}
int mid=l+r>>1;
int ls=x<<1,rs=x<<1|1;
if(nl<=mid)
query(ls,l,mid,nl,nr);
if(nr>mid)
query(rs,mid+1,r,nl,nr);
}
void modify(int x,int l,int r,int nx,int k)
{
if(l==r)
{
segtree[x]=(Segtree){k,k,k,k};
return;
}
int ls=x<<1,rs=x<<1|1;
int mid=l+r>>1;
if(nx<=mid)
modify(ls,l,mid,nx,k);
else
modify(rs,mid+1,r,nx,k);
segtree[x].sum=segtree[ls].sum+segtree[rs].sum;
segtree[x].zong=max(segtree[ls].hou+segtree[rs].qian,max(segtree[ls].zong,segtree[rs].zong));
segtree[x].qian=max(segtree[ls].sum+segtree[rs].qian,segtree[ls].qian);
segtree[x].hou=max(segtree[rs].sum+segtree[ls].hou,segtree[rs].hou);
}
int main()
{
//freopen("P4513.in","r",stdin);
//freopen("P4513.out","w",stdout);
int n=read(),m=read();
for(int i=1;i<=n;++i)
a[i]=read();
build(1,1,n);
while(m--)
{
int p=read();
if(p==1)
{
int l=read(),r=read();
lst=ans=-INF;
query(1,1,n,min(l,r),max(l,r));
printf("%d\n",ans);
}
else
{
int x=read(),s=read();
modify(1,1,n,x,s);
}
}
return 0;
}
by 小恐 @ 2020-05-25 12:00:55
有……有道理啊!
by Werner_Yin @ 2020-05-25 12:00:57
这样就可以考虑到
by 小恐 @ 2020-05-25 12:04:22
A了,蟹蟹