HDU3397 Sequence operation（线段树）
点击打开题目链接，还有一个类似的题，只进行01翻转操作和最大连续查询，HDU3911 Black And White
对一个数列进行如下操作：
Change operations:
0 a b change all characters into '0's in [a , b]1 a b change all characters into '1's in [a , b]
2 a b change all '0's into '1's and change all '1's into '0's in [a, b]
Output operations:
3 a b output the number of '1's in [a, b]
4 a b output the length of the longest continuous '1' string in [a , b]
区间属性
１.最大连续长度=Max(左区间最大，有区间最大，左区间右起最大+有区间左起最大)
2.左端点开始的最大连续长度=左区间最大左连续 或 左区间长度+右区间最大左连续（如果左区间最大左连续==左区间长度）
3.有端点开始的最大连续长度，同上；
注意：
1. 所有翻转的flag都要用 ^操作，避免连续翻转两次而未更新的区间。
2.全置的优先级高于翻转
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
public class Main{
class SegTree{
class node{
int left,right;
int flag,num0,num1;
int max0,l0,r0;
int max1,l1,r1;
int mid(){
return (left+right)>>1;
}
int length(){
return right-left+1;
}
void init(int k){
if(k==0){
num0=max0=l0=r0=length();
num1=l1=r1=max1=0;
}
else
{
max1=l1=r1=num1=length();
num0=max0=l0=r0=0;
}
}
}
node tree[];
SegTree(int maxn){
tree=new node[maxn*5];
}
void init(int left,int right,int idx,int[]a){
tree[idx]=new node();
tree[idx].left=left;
tree[idx].right=right;
tree[idx].flag=-1;
if(left==right){
tree[idx].init(a[left]);
return;
}
int mid=tree[idx].mid();
init(left,mid,idx<<1,a);
init(mid+1,right,(idx<<1)|1,a);
pushup(idx);
}
void update(int left,int right,int idx,int op){
pushdown(idx);
if(tree[idx].left>=left&&tree[idx].right<=right){
if(op==2)
reverse(idx);
else
tree[idx].flag=op;
return;
}
int mid=tree[idx].mid();
if(left<=mid)
update(left,right,idx<<1,op);
if(right>mid)
update(left,right,(idx<<1)|1,op);
pushup(idx);
}
int query(int left,int right,int idx,int type)
{
pushdown(idx);
if(tree[idx].left==left&&tree[idx].right==right){
if(type==3)
return tree[idx].num1;
else
return tree[idx].max1;
}
int mid=tree[idx].mid();
if(right<=mid)
return query(left,right,idx<<1,type);
else if(left>mid)
return query(left,right,(idx<<1)|1,type);
else{
int a=query(left,mid,idx<<1,type);
int b=query(mid+1,right,(idx<<1)|1,type);
if(type==3)
return a+b;
int c = Math.min(tree[idx << 1].r1, mid - left + 1)
+ Math.min(tree[(idx << 1) | 1].l1, right - mid);
return Math.max(Math.max(a,b),c);
}
}
void pushup(int idx){
if(tree[idx].left==tree[idx].right)
return;
pushdown(idx<<1);
pushdown((idx<<1)|1);
tree[idx].num1=tree[idx<<1].num1+tree[(idx<<1)|1].num1;
tree[idx].num0=tree[idx<<1].num0+tree[(idx<<1)|1].num0;
int a=tree[idx<<1].max0;
int b=tree[(idx<<1)|1].max0;
int c=tree[idx<<1].r0+tree[(idx<<1)|1].l0;
tree[idx].max0=Math.max(Math.max(a,b), c);
tree[idx].l0=tree[idx<<1].l0;
if(tree[idx].l0==tree[idx<<1].length())
tree[idx].l0+=tree[(idx<<1)|1].l0;
tree[idx].r0=tree[(idx<<1)|1].r0;
if(tree[(idx<<1)|1].r0==tree[(idx<<1)|1].length())
tree[idx].r0+=tree[idx<<1].r0;
a=tree[idx<<1].max1;
b=tree[(idx<<1)|1].max1;
c=tree[idx<<1].r1+tree[(idx<<1)|1].l1;
tree[idx].max1=Math.max(Math.max(a,b), c);
tree[idx].l1=tree[idx<<1].l1;
if(tree[idx].l1==tree[idx<<1].length())
tree[idx].l1+=tree[(idx<<1)+1].l1;
tree[idx].r1=tree[(idx<<1)|1].r1;
if(tree[(idx<<1)|1].r1==tree[(idx<<1)|1].length())
tree[idx].r1+=tree[idx<<1].r1;
}
void pushdown(int idx){
if(tree[idx].flag==2){
int t=tree[idx].l0;
tree[idx].l0=tree[idx].l1;
tree[idx].l1=t;
t=tree[idx].r0;
tree[idx].r0=tree[idx].r1;
tree[idx].r1=t;
t=tree[idx].max0;
tree[idx].max0=tree[idx].max1;
tree[idx].max1=t;
tree[idx].flag=-1;
t=tree[idx].num0;
tree[idx].num0=tree[idx].num1;
tree[idx].num1=t;
if(tree[idx].left!=tree[idx].right){
t=idx<<1;
reverse(t);
t++;
reverse(t);
}
}
if(tree[idx].flag==1||tree[idx].flag==0){
int t=tree[idx].flag;
tree[idx].init(t);
tree[idx].flag=-1;
if(tree[idx].left!=tree[idx].right){
tree[idx<<1].flag=t;
tree[(idx<<1)|1].flag=t;
}
}
}
void reverse(int idx){
if(tree[idx].flag==2)
tree[idx].flag=-1;
else if(tree[idx].flag==-1)
tree[idx].flag=2;
else
tree[idx].flag^=1;
}
}
StreamTokenizer in = new StreamTokenizer(new BufferedReader(
new InputStreamReader(System.in)));
final int next() throws IOException {
in.nextToken();
return (int) in.nval;
}
SegTree st=new SegTree(100010);
int a[]=new int[100010];
void run() throws IOException{
int t=next();
while(t-->0){
int n=next();
int m=next();
for(int i=1;i<=n;i++)
a[i]=next();
st.init(1, n, 1, a);
while(m-->0){
int k=next();
int a=next()+1;
int b=next()+1;
if(k<3)
st.update(a, b, 1, k);
else
System.out.println(st.query(a, b, 1, k));
}
}
}
public static void main(String[] args) throws IOException {
new Main().run();
}
}