hdu 3397 线段树+区间合并+懒惰标记 好题

Sequence operation

Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 4603    Accepted Submission(s): 1338

Problem Description

lxhgww got a sequence contains n characters which are all '0's or '1's.
We have five operations here:
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]

 

Input

T(T<=10) in the first line is the case number.
Each case has two integers in the first line: n and m (1 <= n , m <= 100000).
The next line contains n characters, '0' or '1' separated by spaces.
Then m lines are the operations:
op a b: 0 <= op <= 4 , 0 <= a <= b < n.

 

Output

For each output operation , output the result.

 

Sample Input

  

   1
10 10
0 0 0 1 1 0 1 0 1 1
1 0 2
3 0 5
2 2 2
4 0 4
0 3 6
2 3 7
4 2 8
1 0 5
0 5 6
3 3 9
  

 

Sample Output

  

   5
2
6
5
  

 

Author

lxhgww&&shǎ崽

 

Source

HDOJ Monthly Contest – 2010.05.01

 

Recommend

lcy

 

很好的一道题，考你有没有理解懒惰标记的本质~~

ps:这是我写的最长的代码了吧~~~

#include <iostream>
#include <cstring>
#include <cstdio>
#define lson pos<<1
#define rson pos<<1|1
using namespace std;
const int MAXN=100005;
int num[MAXN];
struct node
{
    int l,r;
    int msum1,msum0;   //连续最长1和0
    int lsum1,lsum0;   //左起最长
    int rsum1,rsum0;   //右起最长
    int lazy;          //标记
    int sum;           //最长1
    int mid()
    {
        return (l+r)>>1;
    }
};
node tree[MAXN*4];
inline void pushup(int pos)
{
    tree[pos].msum0=max(tree[lson].msum0,tree[rson].msum0);
    tree[pos].msum1=max(tree[lson].msum1,tree[rson].msum1);
    tree[pos].lsum0=tree[lson].lsum0;
    tree[pos].lsum1=tree[lson].lsum1;
    tree[pos].rsum0=tree[rson].rsum0;
    tree[pos].rsum1=tree[rson].rsum1;
    tree[pos].msum0=max(tree[pos].msum0,tree[lson].rsum0+tree[rson].lsum0);
    tree[pos].msum1=max(tree[pos].msum1,tree[lson].rsum1+tree[rson].lsum1);
    int l1=tree[lson].r-tree[lson].l+1;
    int l2=tree[rson].r-tree[rson].l+1;
    if(l1==tree[lson].lsum0)
        tree[pos].lsum0+=tree[rson].lsum0;
    if(l1==tree[lson].lsum1)
        tree[pos].lsum1+=tree[rson].lsum1;
    if(l2==tree[rson].rsum0)
        tree[pos].rsum0+=tree[lson].rsum0;
    if(l2==tree[rson].rsum1)
        tree[pos].rsum1+=tree[lson].rsum1;
    tree[pos].sum=tree[lson].sum+tree[rson].sum;

}
inline void pushdown(int pos)
{
    int x=tree[pos].lazy;
    if(x==0)
    {
        tree[lson].lazy=0;
        tree[lson].sum=0;
        tree[lson].lsum1=tree[lson].rsum1=tree[lson].msum1=0;
        tree[lson].lsum0=tree[lson].rsum0=tree[lson].msum0=tree[lson].r-tree[lson].l+1;

        tree[rson].lazy=0;
        tree[rson].sum=0;
        tree[rson].lsum1=tree[rson].rsum1=tree[rson].msum1=0;
        tree[rson].lsum0=tree[rson].rsum0=tree[rson].msum0=tree[rson].r-tree[rson].l+1;

    }
    else if(x==1)
    {
        tree[lson].lazy=1;
        tree[lson].sum=tree[lson].r-tree[lson].l+1;
        tree[lson].lsum1=tree[lson].rsum1=tree[lson].msum1=tree[lson].r-tree[lson].l+1;
        tree[lson].lsum0=tree[lson].rsum0=tree[lson].msum0=0;

        tree[rson].lazy=1;
        tree[rson].sum=tree[rson].r-tree[rson].l+1;
        tree[rson].lsum1=tree[rson].rsum1=tree[rson].msum1=tree[rson].r-tree[rson].l+1;
        tree[rson].lsum0=tree[rson].rsum0=tree[rson].msum0=0;
    }
    else if(x==2)
    {
        if(tree[lson].l!=tree[lson].r)
            pushdown(lson);
        tree[lson].lazy=2;
        tree[lson].sum=tree[lson].r-tree[lson].l+1-tree[lson].sum;
        int t=tree[lson].lsum1;
        tree[lson].lsum1=tree[lson].lsum0;
        tree[lson].lsum0=t;

        t=tree[lson].rsum1;
        tree[lson].rsum1=tree[lson].rsum0;
        tree[lson].rsum0=t;

        t=tree[lson].msum1;
        tree[lson].msum1=tree[lson].msum0;
        tree[lson].msum0=t;

        if(tree[rson].l!=tree[rson].r)
            pushdown(rson);
        tree[rson].lazy=2;
        tree[rson].sum=tree[rson].r-tree[rson].l+1-tree[rson].sum;
        t=tree[rson].lsum1;
        tree[rson].lsum1=tree[rson].lsum0;
        tree[rson].lsum0=t;

        t=tree[rson].rsum1;
        tree[rson].rsum1=tree[rson].rsum0;
        tree[rson].rsum0=t;

        t=tree[rson].msum1;
        tree[rson].msum1=tree[rson].msum0;
        tree[rson].msum0=t;
    }
    tree[pos].lazy=-1;
}
void build(int l,int r,int pos)
{
    tree[pos].l=l;
    tree[pos].r=r;
    if(l==r)
    {
        int x;
        scanf("%d",&x);
        tree[pos].lazy=-1;
        tree[pos].msum0=!x;
        tree[pos].msum1=x;
        tree[pos].lsum0=!x;
        tree[pos].lsum1=x;
        tree[pos].rsum0=!x;
        tree[pos].rsum1=x;
        tree[pos].sum=x;
        return ;
    }
    int mid=tree[pos].mid();
    build(l,mid,lson);
    build(mid+1,r,rson);
    tree[pos].lazy=-1;
    pushup(pos);
}
void update(int l,int r,int x,int pos)
{
    if(l==tree[pos].l&&r==tree[pos].r)
    {
        if(x==0)
        {
            tree[pos].lazy=0;
            tree[pos].sum=0;
            tree[pos].lsum1=tree[pos].rsum1=tree[pos].msum1=0;
            tree[pos].lsum0=tree[pos].rsum0=tree[pos].msum0=tree[pos].r-tree[pos].l+1;
        }
        else if(x==1)
        {
            tree[pos].lazy=1;
            tree[pos].sum=tree[pos].r-tree[pos].l+1;
            tree[pos].lsum1=tree[pos].rsum1=tree[pos].msum1=tree[pos].r-tree[pos].l+1;
            tree[pos].lsum0=tree[pos].rsum0=tree[pos].msum0=0;
        }
        else
        {
            if(l!=r)          //是1，或0的时候可以直接覆盖，但如果是2的话必须向下更新，，本质~因为下面的状态随上面的变化，
                pushdown(pos);
            tree[pos].lazy=2;
            tree[pos].sum=tree[pos].r-tree[pos].l+1-tree[pos].sum;
            int t=tree[pos].lsum1;
            tree[pos].lsum1=tree[pos].lsum0;
            tree[pos].lsum0=t;

            t=tree[pos].rsum1;
            tree[pos].rsum1=tree[pos].rsum0;
            tree[pos].rsum0=t;

            t=tree[pos].msum1;
            tree[pos].msum1=tree[pos].msum0;
            tree[pos].msum0=t;
        }
        return ;
    }
    pushdown(pos);
    int mid=tree[pos].mid();
    if(r<=mid)
        update(l,r,x,lson);
    else if(l>mid)
        update(l,r,x,rson);
    else
    {
        update(l,mid,x,lson);
        update(mid+1,r,x,rson);
    }
    pushup(pos);
}
int queryR(int l,int r,int pos)
{
    if(r-l+1>=tree[pos].rsum1)
        return tree[pos].rsum1;
    else
        return r-l+1;
}
int queryL(int l,int r,int pos)
{
    if(r-l+1>=tree[pos].lsum1)
        return tree[pos].lsum1;
    else
        return r-l+1;
}
int query(int l,int r,int x,int pos)
{
    if(l==tree[pos].l&&r==tree[pos].r)
    {
        if(x==3)
            return tree[pos].sum;
        else
            return tree[pos].msum1;
    }
    pushdown(pos);
    int mid=tree[pos].mid();
    if(x==3)
    {
        if(r<=mid)
            return query(l,r,x,lson);
        else if(l>mid)
            return query(l,r,x,rson);
        else
            return query(l,mid,x,lson)+query(mid+1,r,x,rson);
    }
    else
    {
        if(r<=mid)
            return query(l,r,x,lson);
        else if(l>mid)
            return query(l,r,x,rson);
        else
        {
            int res=query(l,mid,x,lson);
            res=max(res,query(mid+1,r,x,rson));
            res=max(res,queryR(l,mid,lson)+queryL(mid+1,r,rson));
            return res;
        }
    }
}
int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int n,m;
        scanf("%d%d",&n,&m);
        build(1,n,1);
        int i;
        for(i=0;i<m;i++)
        {
            int a,b,x;
            scanf("%d%d%d",&x,&a,&b);
            a++,b++;
            if(x<=2)
                update(a,b,x,1);
            else
            {
                int res=query(a,b,x,1);
                printf("%d\n",res);
            }
        }
    }
    return 0;
}