HDU 3397 线段树区间合并

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题意：五种操作，0全部置0，1全部置1，2是0变1 1变0，3是询问1的个数，4是询问最长连续的1

思路：推荐先写hdu 3911 ，是这题的简单版，这题注意的地方就是一旦有置0和置1操作，那么2操作的标记就要被覆盖，剩下的操作都是比较精典的区间合并操作了

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <iostream>#include <algorithm>using namespace std;typedef long long ll;typedef unsigned long long ull;const int inf=0x3f3f3f3f;const ll INF=0x3f3f3f3f3f3f3f3fll;const int maxn=100010;int num[maxn];int cnt[maxn<<2],cnt0[maxn<<2],L[maxn<<2],R[maxn<<2],L0[maxn<<2],R0[maxn<<2],rev[maxn<<2];int sum[maxn<<2],flag[maxn<<2];void pushup(int node,int m){    sum[node]=sum[node<<1]+sum[node<<1|1];    L[node]=L[node<<1];R[node]=R[node<<1|1];    if(L[node]==m-(m>>1)) L[node]+=L[node<<1|1];    if(R[node]==m>>1) R[node]+=R[node<<1];    cnt[node]=max(L[node<<1|1]+R[node<<1],max(cnt[node<<1],cnt[node<<1|1]));    L0[node]=L0[node<<1];R0[node]=R0[node<<1|1];    if(L0[node]==m-(m>>1)) L0[node]+=L0[node<<1|1];    if(R0[node]==m>>1) R0[node]+=R0[node<<1];    cnt0[node]=max(L0[node<<1|1]+R0[node<<1],max(cnt0[node<<1],cnt0[node<<1|1]));}void pushdown(int node,int m){    if(flag[node]!=-1){        flag[node<<1]=flag[node<<1|1]=flag[node];        rev[node<<1]=rev[node<<1|1]=0;        if(flag[node]==0){            L0[node<<1]=R0[node<<1]=cnt0[node<<1]=m-(m>>1);            L[node<<1]=R[node<<1]=cnt[node<<1]=sum[node<<1]=0;            L0[node<<1|1]=R0[node<<1|1]=cnt0[node<<1|1]=m>>1;            L[node<<1|1]=R[node<<1|1]=cnt[node<<1|1]=sum[node<<1|1]=0;        }else{            L0[node<<1]=R0[node<<1]=cnt0[node<<1]=0;            L[node<<1]=R[node<<1]=cnt[node<<1]=sum[node<<1]=m-(m>>1);            L0[node<<1|1]=R0[node<<1|1]=cnt0[node<<1|1]=0;            L[node<<1|1]=R[node<<1|1]=cnt[node<<1|1]=sum[node<<1|1]=m>>1;        }        flag[node]=-1;    }    if(rev[node]){        rev[node<<1]^=1;rev[node<<1|1]^=1;        swap(L[node<<1],L0[node<<1]);        swap(R[node<<1],R0[node<<1]);        swap(cnt[node<<1],cnt0[node<<1]);        swap(L[node<<1|1],L0[node<<1|1]);        swap(R[node<<1|1],R0[node<<1|1]);        swap(cnt[node<<1|1],cnt0[node<<1|1]);        sum[node<<1]=m-(m>>1)-sum[node<<1];        sum[node<<1|1]=(m>>1)-sum[node<<1|1];        rev[node]=0;    }}void buildtree(int le,int ri,int node){    rev[node]=0;flag[node]=-1;    if(le==ri){        L[node]=R[node]=cnt[node]=sum[node]=num[le];        L0[node]=R0[node]=cnt0[node]=num[le]^1;        return ;    }    int t=(le+ri)>>1;    buildtree(le,t,node<<1);    buildtree(t+1,ri,node<<1|1);    pushup(node,ri-le+1);}void update(int l,int r,int val,int le,int ri,int node){    if(l<=le&&ri<=r){        if(val==0){            L0[node]=R0[node]=cnt0[node]=ri-le+1;            L[node]=R[node]=cnt[node]=sum[node]=0;        }else{            L0[node]=R0[node]=cnt0[node]=0;            L[node]=R[node]=cnt[node]=sum[node]=ri-le+1;        }        flag[node]=val;rev[node]=0;        return ;    }    pushdown(node,ri-le+1);    int t=(le+ri)>>1;    if(l<=t) update(l,r,val,le,t,node<<1);    if(r>t) update(l,r,val,t+1,ri,node<<1|1);    pushup(node,ri-le+1);}void update_rev(int l,int r,int le,int ri,int node){    if(l<=le&&ri<=r){        swap(L[node],L0[node]);        swap(R[node],R0[node]);        swap(cnt[node],cnt0[node]);        sum[node]=ri-le+1-sum[node];        rev[node]^=1;        return ;    }    pushdown(node,ri-le+1);    int t=(le+ri)>>1;    if(l<=t) update_rev(l,r,le,t,node<<1);    if(r>t) update_rev(l,r,t+1,ri,node<<1|1);    pushup(node,ri-le+1);}int query_sum(int l,int r,int le,int ri,int node){    if(l<=le&&ri<=r) return sum[node];    pushdown(node,ri-le+1);    int t=(le+ri)>>1,ans=0;    if(l<=t) ans+=query_sum(l,r,le,t,node<<1);    if(r>t) ans+=query_sum(l,r,t+1,ri,node<<1|1);    return ans;}int query_lcs(int l,int r,int le,int ri,int node){    if(l<=le&&ri<=r) return cnt[node];    pushdown(node,ri-le+1);    int t=(le+ri)>>1,ans=0;    if(l<=t) ans=max(ans,query_lcs(l,r,le,t,node<<1));    if(r>t) ans=max(ans,query_lcs(l,r,t+1,ri,node<<1|1));    ans=max(ans,min(R[node<<1],t-l+1)+min(L[node<<1|1],r-t));    return ans;}int main(){    int T,n,m,op,a,b;    scanf("%d",&T);    while(T--){        scanf("%d%d",&n,&m);        for(int i=1;i<=n;i++) scanf("%d",&num[i]);        buildtree(1,n,1);        while(m--){            scanf("%d%d%d",&op,&a,&b);            a++;b++;            if(op==0) update(a,b,0,1,n,1);            if(op==1) update(a,b,1,1,n,1);            if(op==2) update_rev(a,b,1,n,1);            if(op==3) printf("%d\n",query_sum(a,b,1,n,1));            if(op==4) printf("%d\n",query_lcs(a,b,1,n,1));        }    }    return 0;}