过了
```cpp
#include <bits/stdc++.h>
using namespace std;
#define int long long
int n,m,a[100005];
struct SegmentTree
{
int l,r;
int change,addreverse;//reverse:1=yes,0=no
int lmax0,rmax0,sum0,kmax0;
int lmax1,rmax1,sum1,kmax1;
} t[100005<<2];
SegmentTree merge(SegmentTree A,SegmentTree b)
{
SegmentTree t;
t.l=A.l,t.r=b.r;
t.lmax0=A.lmax0,t.lmax1=A.lmax1;
t.rmax0=b.rmax0,t.rmax1=b.rmax1;
t.sum0=A.sum0+b.sum0,t.sum1=A.sum1+b.sum1;
t.kmax0=max(max(A.kmax0,b.kmax0),A.rmax0+b.lmax0);
t.kmax1=max(max(A.kmax1,b.kmax1),A.rmax1+b.lmax1);
if(A.lmax0==A.r-A.l+1) t.lmax0+=b.lmax0;
if(A.lmax1==A.r-A.l+1) t.lmax1+=b.lmax1;
if(b.rmax0==b.r-b.l+1) t.rmax0+=A.rmax0;
if(b.rmax1==b.r-b.l+1) t.rmax1+=A.rmax1;
return t;
}
void pushup(int p)
{
t[p].l=t[p*2].l,t[p].r=t[p*2+1].r;
t[p].lmax0=t[p*2].lmax0,t[p].lmax1=t[p*2].lmax1;
t[p].rmax0=t[p*2+1].rmax0,t[p].rmax1=t[p*2+1].rmax1;
t[p].sum0=t[p*2].sum0+t[p*2+1].sum0,t[p].sum1=t[p*2].sum1+t[p*2+1].sum1;
t[p].kmax0=max(max(t[p*2].kmax0,t[p*2+1].kmax0),t[p*2].rmax0+t[p*2+1].lmax0);
t[p].kmax1=max(max(t[p*2].kmax1,t[p*2+1].kmax1),t[p*2].rmax1+t[p*2+1].lmax1);
if(t[p*2].lmax0==t[p*2].r-t[p*2].l+1) t[p].lmax0+=t[p*2+1].lmax0;
if(t[p*2].lmax1==t[p*2].r-t[p*2].l+1) t[p].lmax1+=t[p*2+1].lmax1;
if(t[p*2+1].rmax0==t[p*2+1].r-t[p*2+1].l+1) t[p].rmax0+=t[p*2].rmax0;
if(t[p*2+1].rmax1==t[p*2+1].r-t[p*2+1].l+1) t[p].rmax1+=t[p*2].rmax1;
}
void spread(int p)
{
if(t[p].change!=-1)
{
t[p*2].lmax1=t[p*2].rmax1=t[p*2].kmax1=t[p*2].sum1=(t[p*2].r-t[p*2].l+1)*t[p].change;
t[p*2].lmax0=t[p*2].rmax0=t[p*2].kmax0=t[p*2].sum0=(t[p*2].r-t[p*2].l+1)*(!t[p].change);
t[p*2+1].lmax1=t[p*2+1].rmax1=t[p*2+1].kmax1=t[p*2+1].sum1=(t[p*2+1].r-t[p*2+1].l+1)*t[p].change;
t[p*2+1].lmax0=t[p*2+1].rmax0=t[p*2+1].kmax0=t[p*2+1].sum0=(t[p*2+1].r-t[p*2+1].l+1)*(!t[p].change);
t[p*2].change=t[p*2+1].change=t[p].change;
t[p*2].addreverse=t[p*2+1].addreverse=0;
t[p].change=-1;
}
else if(t[p].addreverse)
{
swap(t[p*2].sum0,t[p*2].sum1);
swap(t[p*2].lmax0,t[p*2].lmax1);
swap(t[p*2].rmax0,t[p*2].rmax1);
swap(t[p*2].kmax0,t[p*2].kmax1);
swap(t[p*2+1].sum0,t[p*2+1].sum1);
swap(t[p*2+1].lmax0,t[p*2+1].lmax1);
swap(t[p*2+1].rmax0,t[p*2+1].rmax1);
swap(t[p*2+1].kmax0,t[p*2+1].kmax1);
if(t[p*2].change!=-1) t[p*2].change^=1;
else t[p*2].addreverse^=1;
if(t[p*2+1].change!=-1) t[p*2+1].change^=1;
else t[p*2+1].addreverse^=1;
t[p].addreverse=0;
}
}
void build(int l,int r,int p)
{
t[p].l=l,t[p].r=r,t[p].change=-1,t[p].addreverse=0;
if(l==r) return (void)(t[p].lmax0=t[p].rmax0=t[p].kmax0=t[p].sum0=(a[l]==0),t[p].lmax1=t[p].rmax1=t[p].kmax1=t[p].sum1=(a[l]==1));
int mid=(l+r)>>1;
build(l,mid,p*2);
build(mid+1,r,p*2+1);
pushup(p);
}
void change0(int l,int r,int p)
{
if(l<=t[p].l&&t[p].r<=r)
{
t[p].lmax0=t[p].rmax0=t[p].kmax0=t[p].sum0=t[p].r-t[p].l+1;
t[p].lmax1=t[p].rmax1=t[p].kmax1=t[p].sum1=0;
t[p].change=0,t[p].addreverse=0;
return ;
}
spread(p);
int mid=(t[p].l+t[p].r)>>1;
if(l<=mid) change0(l,r,p*2);
if(r>mid) change0(l,r,p*2+1);
pushup(p);
}
void change1(int l,int r,int p)
{
if(l<=t[p].l&&t[p].r<=r)
{
//cout<<t[p].l<<' '<<t[p].r<<endl;
t[p].lmax1=t[p].rmax1=t[p].kmax1=t[p].sum1=t[p].r-t[p].l+1;
t[p].lmax0=t[p].rmax0=t[p].kmax0=t[p].sum0=0;
t[p].change=1,t[p].addreverse=0;
return ;
}
spread(p);
int mid=(t[p].l+t[p].r)>>1;
if(l<=mid) change1(l,r,p*2);
if(r>mid) change1(l,r,p*2+1);
pushup(p);
}
void changereverse(int l,int r,int p)
{
if(l<=t[p].l&&t[p].r<=r)
{
swap(t[p].lmax0,t[p].lmax1),swap(t[p].rmax0,t[p].rmax1);
swap(t[p].kmax0,t[p].kmax1),swap(t[p].sum0,t[p].sum1);
if(t[p].change!=-1) t[p].change^=1; else t[p].addreverse^=1;
return ;
}
spread(p);
int mid=(t[p].l+t[p].r)>>1;
if(l<=mid) changereverse(l,r,p*2);
if(r>mid) changereverse(l,r,p*2+1);
pushup(p);
}
int asksum(int l,int r,int p)
{
if(l<=t[p].l&&t[p].r<=r) return t[p].sum1;
spread(p);
int mid=(t[p].l+t[p].r)>>1,cnt=0;
if(l<=mid) cnt+=asksum(l,r,p*2);
if(r>mid) cnt+=asksum(l,r,p*2+1);
return cnt;
}
SegmentTree ask(int l,int r,int p)
{
if(l<=t[p].l&&t[p].r<=r) return t[p];
spread(p);
int mid=(t[p].l+t[p].r)>>1;
if(l<=mid&&r>mid) return merge(ask(l,r,p*2),ask(l,r,p*2+1));
else if(l<=mid) return ask(l,r,p*2);
else return ask(l,r,p*2+1);
}
signed main()
{
ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
cin>>n>>m;
for(int i=1; i<=n; i++) cin>>a[i];
build(1,n,1);
while(m--)
{
int op,l,r;
cin>>op>>l>>r;
l++,r++;
if(op==0) change0(l,r,1);
else if(op==1) change1(l,r,1);
else if(op==2) changereverse(l,r,1);
else if(op==3) cout<<asksum(l,r,1)<<endl;
else if(op==4) cout<<ask(l,r,1).kmax1<<endl;
}
return 0;
}
```cpp
by sunkaihuan @ 2024-02-05 11:42:45
merge里这一段去掉||后面的内容，否则会因为合并左/右信息时因为没有01前后缀而错误
```cpp
if(A.lmax0==A.r-A.l+1||!A.lmax0) t.lmax0+=b.lmax0;
if(A.lmax1==A.r-A.l+1||!A.lmax1) t.lmax1+=b.lmax1;
if(b.rmax0==b.r-b.l+1||!b.rmax0) t.rmax0+=A.rmax0;
if(b.rmax1==b.r-b.l+1||!b.rmax1) t.rmax1+=A.rmax1;
```
by sunkaihuan @ 2024-02-05 11:45:04
十分感谢，已关！！！ @[sunkaihuan](/user/504535)
by Binah_cyc @ 2024-02-05 11:47:39