There are a bunch of stones on the beach; Stone color is white or black. Little Sheep has a magic brush, she can change the color of a continuous stone, black to white, white to black. Little Sheep like black very much, so she want to know the longest period of consecutive black stones in a range [i, j].
Input
There are multiple cases, the first line of each case is an integer n(1<= n <= 10^5), followed by n integer 1 or 0(1 indicates black stone and 0 indicates white stone), then is an integer M(1<=M<=10^5) followed by M operations formatted as x i j(x = 0 or 1) , x=1 means change the color of stones in range[i,j], and x=0 means ask the longest period of consecutive black stones in range[i,j]
Output
When x=0 output a number means the longest length of black stones in range [i,j].
Sample Input
4
1 0 1 0
5
0 1 4
1 2 3
0 1 4
1 3 3
0 4 4
Sample Output
1
2
0
题解:分别记录左连续 和 右连续 即可
此题的升级版,整体改变和异或的结合 点击查看链接
#include<iostream>
#include<cstdio>
using namespace std;
const int N=1e5+10;
struct node
{
int l,r,len;
int l0,r0,max0;
int l1,r1,max1;
int laz;
}tree[N<<2];
int n,q,x;
void pushup(int cur)
{
tree[cur].l0=tree[cur<<1].l0;
if(tree[cur<<1].l0==tree[cur<<1].len)
tree[cur].l0+=tree[cur<<1|1].l0;
tree[cur].r0=tree[cur<<1|1].r0;
if(tree[cur<<1|1].r0==tree[cur<<1|1].len)
tree[cur].r0+=tree[cur<<1].r0;
tree[cur].max0=max(tree[cur<<1].max0,tree[cur<<1|1].max0);
tree[cur].max0=max(tree[cur].max0,tree[cur<<1].r0+tree[cur<<1|1].l0);
tree[cur].l1=tree[cur<<1].l1;
if(tree[cur<<1].l1==tree[cur<<1].len)
tree[cur].l1+=tree[cur<<1|1].l1;
tree[cur].r1=tree[cur<<1|1].r1;
if(tree[cur<<1|1].r1==tree[cur<<1|1].len)
tree[cur].r1+=tree[cur<<1].r1;
tree[cur].max1=max(tree[cur<<1].max1,tree[cur<<1|1].max1);
tree[cur].max1=max(tree[cur].max1,tree[cur<<1].r1+tree[cur<<1|1].l1);
}
void build(int l,int r,int cur)
{
tree[cur].laz=0;
tree[cur].l=l;
tree[cur].r=r;
tree[cur].len=r-l+1;
if(l==r)
{
scanf("%d",&x);
tree[cur].l1=tree[cur].r1=tree[cur].max1=(x==1);
tree[cur].l0=tree[cur].r0=tree[cur].max0=(x==0);
return;
}
int mid=(r+l)>>1;
build(l,mid,cur<<1);
build(mid+1,r,cur<<1|1);
pushup(cur);
}
void change(int cur)
{
swap(tree[cur].l0,tree[cur].l1);
swap(tree[cur].r0,tree[cur].r1);
swap(tree[cur].max0,tree[cur].max1);
}
void pushdown(int cur)
{
if(tree[cur].laz)
{
tree[cur<<1].laz^=1;
tree[cur<<1|1].laz^=1;
change(cur<<1);
change(cur<<1|1);
tree[cur].laz=0;
}
}
void update(int pl,int pr,int cur)
{
if(pl<=tree[cur].l&&tree[cur].r<=pr)
{
tree[cur].laz^=1;
change(cur);
return;
}
pushdown(cur);
if(pl<=tree[cur<<1].r) update(pl,pr,cur<<1);
if(pr>=tree[cur<<1|1].l) update(pl,pr,cur<<1|1);
pushup(cur);
}
int query(int pl,int pr,int cur)
{
if(pl<=tree[cur].l&&tree[cur].r<=pr)
{
return tree[cur].max1;
}
pushdown(cur);
if(pr<=tree[cur<<1].r) return query(pl,pr,cur<<1);
else if(pl>=tree[cur<<1|1].l) return query(pl,pr,cur<<1|1);
else
{
int res=min(pr,tree[cur<<1|1].l1+tree[cur<<1|1].l-1)-max(pl,tree[cur<<1].r-tree[cur<<1].r1+1)+1;
res=max(res,query(pl,pr,cur<<1));
res=max(res,query(pl,pr,cur<<1|1));
return res;
}
}
int main()
{
int op,l,r;
while(~scanf("%d",&n))
{
build(1,n,1);
scanf("%d",&q);
while(q--)
{
scanf("%d%d%d",&op,&l,&r);
if(op==0)
{
printf("%d\n",query(l,r,1));
}
else
{
update(l,r,1);
}
}
}
return 0;
}