AC日记——开关灯 codevs 1690

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

#define maxn 100005

struct TreeNodeType {
    int l,r,dis,lit,mid,flag;
};
struct TreeNodeType tree[maxn<<2];

int n,m;

inline void in(int &now)
{
    char Cget=getchar();now=0;
    while(Cget>‘9‘||Cget<‘0‘) Cget=getchar();
    while(Cget>=‘0‘&&Cget<=‘9‘)
    {
        now=now*10+Cget-‘0‘;
        Cget=getchar();
    }
}

void tree_build(int now,int l,int r)
{
    tree[now].l=l,tree[now].r=r,tree[now].lit=r-l+1;
    if(l==r) return ;
    tree[now].mid=l+r>>1;
    tree_build(now<<1,l,tree[now].mid);
    tree_build(now<<1|1,tree[now].mid+1,r);
}

inline void tree_down(int now)
{
    tree[now<<1].flag^=1,tree[now<<1|1].flag^=1;
    tree[now<<1].dis=tree[now<<1].lit-tree[now<<1].dis;
    tree[now<<1|1].dis=tree[now<<1|1].lit-tree[now<<1|1].dis;
    tree[now].flag=0;
}

void tree_change(int now,int l,int r)
{
    if(tree[now].l==l&&tree[now].r==r)
    {
        tree[now].dis=tree[now].lit-tree[now].dis;
        tree[now].flag^=1;
        return ;
    }
    if(tree[now].flag) tree_down(now);
    if(l>tree[now].mid) tree_change(now<<1|1,l,r);
    else if(r<=tree[now].mid) tree_change(now<<1,l,r);
    else
    {
        tree_change(now<<1,l,tree[now].mid);
        tree_change(now<<1|1,tree[now].mid+1,r);
    }
    tree[now].dis=tree[now<<1].dis+tree[now<<1|1].dis;
}

int tree_query(int now,int l,int r)
{
    if(tree[now].l==l&&tree[now].r==r) return tree[now].dis;
    if(tree[now].flag) tree_down(now);
    if(l>tree[now].mid) tree_query(now<<1|1,l,r);
    else if(r<=tree[now].mid) tree_query(now<<1,l,r);
    else return tree_query(now<<1,l,tree[now].mid)+tree_query(now<<1|1,tree[now].mid+1,r);
}

int main()
{
    in(n),in(m);int op,u,v;
    tree_build(1,1,n);
    for(;m--;)
    {
        in(op),in(u),in(v);
        if(op) printf("%d\n",tree_query(1,u,v));
        else tree_change(1,u,v);
    }
    return 0;
}