HDu 5029 Relief grainセグメントツリー

<pre style="font-family: 'Courier New';"><pre name="code" class="html">//  [1 , n] 
//            2
//p a b c
//  [a,b]       c
//q a b
// [a,b]        
//      30   
//         
//          
#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std ;
const int maxn = 1e6+10 ;
#define left v<<1
#define right v<<1|1
struct node
{
    int x ;
    int op ;
    int l , r ;
}tree[maxn<<2] ;
void build(int l , int r , int v)
{
    tree[v].l = l ;
    tree[v].r = r ;
    tree[v].op = 0 ;
    tree[v].x = 1<<2 ;
    if(l == r)
    return ;
    int mid = (l + r) >> 1 ;
    build(l , mid , left) ;
    build(mid+1 , r , right) ;
}
void push_down(int v)
{
    if(tree[v].op)
    {
        tree[left].x = tree[right].x = 1<<tree[v].op ;
        tree[left].op = tree[right].op = tree[v].op ;
        tree[v].op = 0 ;
    }
}
void update(int l , int r ,int v , int co)
{
    if(l <= tree[v].l && tree[v].r <= r)
    {
        tree[v].x = 1<<co ;
        tree[v].op = co ;
        return   ;
    }
    push_down(v) ;
    int mid = (tree[v].l + tree[v].r) >> 1 ;
    if(l <= mid)update(l , r , left , co) ;
    if(r > mid)update(l , r , right ,co) ;
    tree[v].x = tree[left].x|tree[right].x ;
}
int query(int l , int r , int v)
{
    if(l <= tree[v].l && tree[v].r <= r)
    return tree[v].x ;
    push_down(v) ;
    int mid = (tree[v].l + tree[v].r) >> 1 ;
    int ans = 0 ;
    if(l <= mid)ans |= query(l , r , left) ;
    if(r > mid)ans |= query(l , r , right) ;
    tree[v].x = tree[left].x|tree[right].x ;
    return ans ;
}
int main()
{
     //freopen("in.txt" , "r" , stdin) ;
     int n , m ;
     while(scanf("%d%d" , &n , &m) && (n+m))
     {
         build(1 , n , 1) ;
         char ch[5] ;
         while(m--)
         {
             scanf("%s" , ch) ;
             int a , b , c ;
             if(ch[0] == 'P')
             {
                 scanf("%d%d%d" , &a , &b , &c) ;
                 update(a , b , 1 , c)  ;
             }
             else if(ch[0] == 'Q')
             {
                 scanf("%d%d" , &a , &b) ;
                 int sum = query(a , b , 1) ;
                 int ans = 0 ;
                 int flag = 0 ;
                 for(int i = 1;i <= 30;i++)
                 if(sum&(1<<i))
                 {
                     if(flag)printf(" ");
                     printf("%d" , i) ;
                     flag = 1 ;
                 }
                 puts("") ;
             }
         }
     }
     return 0 ;
}