POJ 2777 Count Color(线段树 区间更新)

#include <stdio.h>
#include <string.h>
#include <iostream>
using namespace std;
#define N 100001
#define LL __int64
int p[4*N],lz[4*N];
void pushup(int rt)
{
p[rt] = p[rt<<1]|p[rt<<1|1];
}
void pushdown(int rt)
{
if(lz[rt])
{
lz[rt<<1] = lz[rt];
lz[rt<<1|1] = lz[rt];
p[rt<<1] = lz[rt];
p[rt<<1|1] = lz[rt];
lz[rt] = 0;
}
}
void build(int l,int r,int rt)
{
int m;
lz[rt] = 0;
if(l == r)
{
p[rt] = 1;
return ;
}
m = (l+r)>>1;
build(l,m,rt<<1);
build(m+1,r,rt<<1|1);
pushup(rt);
}
int query(int L,int R,int l,int r,int rt)
{
int m,ans;
ans = 0;
if(l >= L&&r <= R)
{
return p[rt];
}
pushdown(rt);
m = (l+r)>>1;
if(L <= m)
ans |= query(L,R,l,m,rt<<1);
if(R > m)
ans |= query(L,R,m+1,r,rt<<1|1);
return ans;

}
void update(int L,int R,int l,int r,int rt,int sc)
{
int m;
if(l >= L &&r <= R)
{
lz[rt] = sc;
p[rt] = sc;
return ;
}
pushdown(rt);
m = (l+r)>>1;
if(L <= m) update(L,R,l,m,rt<<1,sc);
if(R > m) update(L,R,m+1,r,rt<<1|1,sc);
pushup(rt);
}
int main()
{
int n,m,k,i,a,b,c,ans,t,j;
char ch[11];
while(scanf("%d%d%d",&n,&m,&k)!=EOF)
{
build(1,n,1);
for(i = 1;i <= k;i ++)
{
scanf("%s",ch);
if(ch[0] == 'C')
{
scanf("%d%d%d",&a,&b,&c);
if(a > b) swap(a,b);
update(a,b,1,n,1,1<<(c-1));
}
else
{
scanf("%d%d",&a,&b);
if(a > b) swap(a,b);
ans = query(a,b,1,n,1);
t = 0;
for(j = 0;j < m;j ++)
if(ans&(1<<j))
t ++;
printf("%d\n",t);
}
}
}
return 0;
}