题目链接：http://www.lydsy.com/JudgeOnline/problem.php?id=1858
需要维护连续的0、连续的1、3种lazy和一个和
让我调到半夜的一个地方：修改时一定要先pushdown！！！
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#include<bits/stdc++.h> #define MAXN 100010 using namespace std; inline int rd(){ int x=0,y=1;char c=getchar(); while(c<'0' || c>'9'){if(c=='-')y=-y;c=getchar();} while(c>='0'&&c<='9')x=x*10+c-'0',c=getchar(); return x*y; } struct node{ int l,r,len; int lazy,sum; int ml1,mr1,mm1; int ml0,mr0,mm0; }tree[MAXN*6]; int n,m; inline void pushup(int x){ int l=x*2,r=x*2+1; tree[x].sum=tree[l].sum+tree[r].sum; tree[x].mm1=tree[l].mr1+tree[r].ml1; tree[x].mm0=tree[l].mr0+tree[r].ml0; if(tree[l].ml1==tree[l].len)tree[x].ml1=tree[l].ml1+tree[r].ml1; else tree[x].ml1=tree[l].ml1; if(tree[l].ml0==tree[l].len)tree[x].ml0=tree[l].ml0+tree[r].ml0; else tree[x].ml0=tree[l].ml0; if(tree[r].mr1==tree[r].len)tree[x].mr1=tree[r].mr1+tree[l].mr1; else tree[x].mr1=tree[r].mr1; if(tree[r].mr0==tree[r].len)tree[x].mr0=tree[r].mr0+tree[l].mr0; else tree[x].mr0=tree[r].mr0; tree[x].mm1=max(tree[x].mm1,max(tree[l].mm1,tree[r].mm1)); tree[x].mm0=max(tree[x].mm0,max(tree[l].mm0,tree[r].mm0)); } void build(int x,int l,int r){ tree[x].l=l; tree[x].r=r; tree[x].len=r-l+1; if(l==r){ tree[x].sum=tree[x].ml1=tree[x].mr1=tree[x].mm1=rd(); tree[x].ml0=tree[x].mr0=tree[x].mm0=tree[x].sum^1; return; } int mid=(l+r)/2; build(x*2,l,mid); build(x*2+1,mid+1,r); pushup(x); } inline void Rev(int x){ swap(tree[x].ml1,tree[x].ml0); swap(tree[x].mr1,tree[x].mr0); swap(tree[x].mm1,tree[x].mm0); } inline void pushdown(int x){ int l=x*2,r=x*2+1; if(tree[x].lazy==1){ tree[l].lazy=tree[r].lazy=1; tree[l].sum=0; tree[r].sum=0; tree[l].ml1=tree[l].mr1=tree[l].mm1=0; tree[r].ml1=tree[r].mr1=tree[r].mm1=0; tree[l].ml0=tree[l].mr0=tree[l].mm0=tree[l].len; tree[r].ml0=tree[r].mr0=tree[r].mm0=tree[r].len; } if(tree[x].lazy==2){ tree[l].lazy=tree[r].lazy=2; tree[l].sum=tree[l].len; tree[r].sum=tree[r].len; tree[l].ml1=tree[l].mr1=tree[l].mm1=tree[l].len; tree[r].ml1=tree[r].mr1=tree[r].mm1=tree[r].len; tree[l].ml0=tree[l].mr0=tree[l].mm0=0; tree[r].ml0=tree[r].mr0=tree[r].mm0=0; } if(tree[x].lazy==3){ if(tree[l].lazy==1)tree[l].lazy=2; else if(tree[l].lazy==2)tree[l].lazy=1; else if(tree[l].lazy==3)tree[l].lazy=0; else tree[l].lazy=3; if(tree[r].lazy==1)tree[r].lazy=2; else if(tree[r].lazy==2)tree[r].lazy=1; else if(tree[r].lazy==3)tree[r].lazy=0; else tree[r].lazy=3; tree[l].sum=tree[l].len-tree[l].sum; tree[r].sum=tree[r].len-tree[r].sum; Rev(l);Rev(r); } tree[x].lazy=0; } void modify(int x,int l,int r,int k){ pushdown(x); if(tree[x].l==l && tree[x].r==r){ tree[x].lazy=k; if(k==1){ tree[x].sum=0; tree[x].ml1=tree[x].mr1=tree[x].mm1=0; tree[x].ml0=tree[x].mr0=tree[x].mm0=tree[x].len; } if(k==2){ tree[x].sum=tree[x].len; tree[x].ml1=tree[x].mr1=tree[x].mm1=tree[x].len; tree[x].ml0=tree[x].mr0=tree[x].mm0=0; } if(k==3){ tree[x].sum=tree[x].len-tree[x].sum; Rev(x); } return; } int mid=(tree[x].l+tree[x].r)/2; if(r<=mid)modify(x*2,l,r,k); else if(l>mid)modify(x*2+1,l,r,k); else modify(x*2,l,mid,k),modify(x*2+1,mid+1,r,k); pushup(x); } int query1(int x,int l,int r){ if(tree[x].l==l && tree[x].r==r)return tree[x].sum; pushdown(x); int mid=(tree[x].l+tree[x].r)/2; if(r<=mid)return query1(x*2,l,r); else if(l>mid)return query1(x*2+1,l,r); else return query1(x*2,l,mid)+query1(x*2+1,mid+1,r); } inline int queryl(int x,int l,int r){ if(tree[x].ml1+l>r)return r-l+1; return tree[x].ml1; } inline int queryr(int x,int l,int r){ if(tree[x].mr1+l>r)return r-l+1; return tree[x].mr1; } int query2(int x,int l,int r){ if(tree[x].l==l && tree[x].r==r)return max(tree[x].mm1,max(tree[x].ml1,tree[x].mr1)); pushdown(x); int mid=(tree[x].l+tree[x].r)/2; if(r<=mid)return query2(x*2,l,r); else if(l>mid)return query2(x*2+1,l,r); else return max(max(query2(x*2,l,mid),query2(x*2+1,mid+1,r)),queryr(x*2,l,mid)+queryl(x*2+1,mid+1,r)); } int main(){ n=rd(),m=rd(); build(1,1,n); int op,x,y; while(m--){ op=rd(),x=rd()+1,y=rd()+1; if(op<3)modify(1,x,y,op+1); if(op==3)printf("%d\n",query1(1,x,y)); if(op==4)printf("%d\n",query2(1,x,y)); } return 0; } |
