没什么好说的，细节题
注释放代码里
#include<bits/stdc++.h> using namespace std; const int N=1e5+7; template <class I> inline void read(I &x){ int f=1; char c; for(c=getchar();c<'0'||c>'9';c=getchar()) if(c=='-') f=-1; for(x=0;c>='0'&&c<='9';x=(x<<3)+(x<<1)+(c&15),c=getchar()); x*=f; } int n,m; bool a[N]; struct tree{ int l=1<<30,r=0,sum=0,lm1=0,rm1=0,lm0=0,rm0=0,mx1=0,mx0=0,op1=-1; bool xr=0; tree(int l=0,int r=0,int sum=0,int lm1=0,int rm1=0,int lm0=0,int rm0=0,int mx1=0,int mx0=0,int op1=-1,bool xr=0): l(l),r(r),sum(sum),lm1(lm1),rm1(rm1),lm0(lm0),rm0(rm0),mx1(mx1),mx0(mx0),op1(op1),xr(xr){} #define l(x) t[x].l #define r(x) t[x].r #define mx1(x) t[x].mx1 #define mx0(x) t[x].mx0 #define sum(x) t[x].sum #define lm1(x) t[x].lm1 #define rm1(x) t[x].rm1 #define lm0(x) t[x].lm0 #define rm0(x) t[x].rm0 #define op1(x) t[x].op1 #define xr(x) t[x].xr }t[4*N]; inline void c1(int p,bool v){ sum(p)=v*(r(p)-l(p)+1); lm1(p)=v*(r(p)-l(p)+1); rm1(p)=v*(r(p)-l(p)+1); mx1(p)=v*(r(p)-l(p)+1); lm0(p)=(v^1)*(r(p)-l(p)+1); rm0(p)=(v^1)*(r(p)-l(p)+1); mx0(p)=(v^1)*(r(p)-l(p)+1); op1(p)=v; xr(p)=0; return; } inline void c2(int p){ sum(p)=r(p)-l(p)+1-sum(p); swap(lm1(p),lm0(p)); swap(rm1(p),rm0(p)); swap(mx1(p),mx0(p)); xr(p)^=1;//注意异或 if(op1(p)!=-1) op1(p)^=1,xr(p)=0; return; } inline void pd(int p){ if(l(p)==r(p)) return; if(op1(p)!=-1){ c1(p*2,op1(p)); c1(p*2+1,op1(p)); op1(p)=-1; } if(xr(p)){ c2(p*2); c2(p*2+1); xr(p)=0; return; } } inline void upd(int p){ sum(p)=sum(p*2)+sum(p*2+1); if(lm1(p*2)==r(p*2)-l(p*2)+1) lm1(p)=lm1(p*2)+lm1(p*2+1); else lm1(p)=lm1(p*2); if(rm1(p*2+1)==r(p*2+1)-l(p*2+1)+1) rm1(p)=rm1(p*2)+rm1(p*2+1); else rm1(p)=rm1(p*2+1); if(lm0(p*2)==r(p*2)-l(p*2)+1) lm0(p)=lm0(p*2)+lm0(p*2+1); else lm0(p)=lm0(p*2); if(rm0(p*2+1)==r(p*2+1)-l(p*2+1)+1) rm0(p)=rm0(p*2)+rm0(p*2+1); else rm0(p)=rm0(p*2+1); mx0(p)=max(mx0(p*2),max(mx0(p*2+1),rm0(p*2)+lm0(p*2+1))); mx1(p)=max(mx1(p*2),max(mx1(p*2+1),rm1(p*2)+lm1(p*2+1))); return; } void build(int p,int l,int r){ l(p)=l,r(p)=r,op1(p)=-1; if(l==r){ c1(p,a[l]); return; } int mid=(l+r)/2; build(p*2,l,mid); build(p*2+1,mid+1,r); upd(p); return; } void change1(int p,int l,int r,bool v){ if(l(p)>=l&&r(p)<=r){ c1(p,v); return; } pd(p); int mid=(l(p)+r(p))/2; if(mid>=l) change1(p*2,l,r,v); if(mid+1<=r) change1(p*2+1,l,r,v); upd(p); return; } void change2(int p,int l,int r){ if(l(p)>=l&&r(p)<=r){ c2(p); return; } pd(p); int mid=(l(p)+r(p))/2; if(mid>=l) change2(p*2,l,r); if(mid<r) change2(p*2+1,l,r); upd(p); return; } int ask1(int p,int l,int r){ if(l(p)>=l&&r(p)<=r){ return sum(p); } pd(p); int res=0; int mid=(l(p)+r(p))/2; if(mid>=l) res+=ask1(p*2,l,r); if(mid<r) res+=ask1(p*2+1,l,r); upd(p); return res; } tree ask2(int p,int l,int r){//写这一段一定要注意各种边界问题之类的 if(l(p)>=l&&r(p)<=r){ return t[p]; } pd(p); tree res,res1,res2; int mid=(l(p)+r(p))/2; if(mid>=l) res1=ask2(p*2,l,r); if(mid<r) res2=ask2(p*2+1,l,r); if(mid<l) return res2; if(mid>=r) return res1; res.l=res1.l,res.r=res2.r; if(res1.lm1==res1.r-res1.l+1) res.lm1=res1.lm1+res2.lm1; else res.lm1=res1.lm1; if(res2.rm1==res2.r-res2.l+1) res.rm1=res2.rm1+res1.rm1; else res.rm1=res2.rm1; res.mx1=max(res1.mx1,max(res2.mx1,res1.rm1+res2.lm1)); return res; } int main(){ //freopen("1.in","r",stdin); //freopen("1.out","w",stdout); read(n),read(m); for(int i=1;i<=n;i++) read(a[i]); build(1,1,n); for(int i=1;i<=m;i++){ int op,A,b; read(op),read(A),read(b); A++,b++; if(op==0) change1(1,A,b,0); if(op==1) change1(1,A,b,1); if(op==2) change2(1,A,b); if(op==3) printf("%d\n",ask1(1,A,b)); if(op==4) printf("%d\n",ask2(1,A,b).mx1); } return 0; }
来源：博客园
作者：丶带带派大星
链接：https://www.cnblogs.com/Hikigaya/p/11684475.html