【POJ】2777 Count Color

#include<cstdio>
#include<cstring>
#define MAXN 100010
int cnt;
struct node
{
    int bit,val;
};
node tree[MAXN<<2];
inline void swap(int &x,int &y)
{
    int temp=x;
    x=y;
    y=temp;
}
inline void PushUp(int rt)
{
    tree[rt].bit=tree[rt<<1].bit|tree[rt<<1|1].bit;
}
inline void PushDown(int rt)
{
    if(tree[rt].val)
    {
        tree[rt<<1]=tree[rt<<1|1]=tree[rt];
        tree[rt].val=0;
    }
}
void Update(int x,int y,int val,int L,int R,int rt)
{
    if(x<=L&&R<=y)
    {
        tree[rt].val=val;
        tree[rt].bit=1<<(val-1);
    }
    else
    {
        int mid=(L+R)>>1;
        PushDown(rt);
        if(mid>=x)
            Update(x,y,val,L,mid,rt<<1);
        if(y>mid)
            Update(x,y,val,mid+1,R,rt<<1|1);
        PushUp(rt);
    }
}
void Query(int x,int y,int L,int R,int rt)
{
    if(x<=L&&R<=y)
        cnt|=tree[rt].bit;
    else
    {
        int mid=(L+R)>>1;
        PushDown(rt);
        if(mid>=x)
            Query(x,y,L,mid,rt<<1);
        if(y>mid)
            Query(x,y,mid+1,R,rt<<1|1);
    }
}
int main()
{
    char ch;
    int n,t,q,a,b,c,ans,i;
    while(~scanf("%d%d%d",&n,&t,&q))
    {
        memset(tree,0,sizeof(tree));
        Update(1,n,1,1,n,1);
        while(q--)
        {
            scanf(" %c%d%d",&ch,&a,&b);
            if(a>b)
                swap(a,b);
            if(ch=='C')
            {
                scanf("%d",&c);
                Update(a,b,c,1,n,1);
            }
            else
            {
                cnt=0;
                Query(a,b,1,n,1);
                for(i=ans=0;i<t;i++)
                {
                    if(cnt&(1<<i))
                        ans++;
                }
                printf("%d\n",ans);
            }
        }
    }
    return 0;
}