线段树统计颜色

先压位存储  类似一个bitset 

输出答案的时候看看有几个1就好了

pushup的话或一下左右区间

#include<iostream>
#include<cstring>
using namespace std;

const int N = 1e6+10;

struct Segment{
	int l,r,id,lz;
}tr[N<<2];

void pushup(int u){
	tr[u].id = tr[u<<1].id | tr[u<<1|1].id;
}

void pushdown(int u){
	if(tr[u].lz){
		tr[u<<1].lz  = tr[u].lz;
		tr[u<<1|1].lz = tr[u].lz;
		
		tr[u<<1].id = tr[u].id;
		tr[u<<1|1].id = tr[u].id;
		
		
		tr[u].lz = 0;
	}
}

void build(int u,int l,int r){
	tr[u] = {l,r,1,0};
	if(l==r)return;
	int mid = l+r>>1;
	build(u<<1,l,mid),build(u<<1|1,mid+1,r);
	pushup(u);
}

void modify(int u,int l,int r,int c){
	if(l<=tr[u].l&&tr[u].r<=r){
		tr[u].id = c;tr[u].lz = 1;return;
	}
	
	pushdown(u);
	
	int mid = tr[u].l+tr[u].r>>1;
	if(l<=mid)modify(u<<1,l,r,c);
	if(r>mid)modify(u<<1|1,l,r,c);
	
	pushup(u);
	
}

int query(int u,int l,int r){
	if(l<=tr[u].l&&tr[u].r<=r)return tr[u].id;
	pushdown(u);
	int mid = tr[u].l+tr[u].r>>1;
	int ans = 0;
	if(l<=mid)ans|=query(u<<1,l,r);
	if(r>mid)ans|=query(u<<1|1,l,r);
	return ans;
}

int lowbit(int x){return x&-x;}
int cal(int x){
	int res = 0;
	for(int i=x;i;i-=lowbit(i))res++;
	return res;
}


int main()
{
	int n,m,q;
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	cin>>n>>m>>q;
	build(1,1,n);
	
	while(q--){
		char c;cin>>c;int l,r;cin>>l>>r;
		if(l>r)swap(l,r);
		
		if(c=='C'){
			int x;cin>>x;
			modify(1,l,r,1<<(x-1));
		}else{
			cout<<cal(query(1,l,r))<<"\n";
		}
	}
	
	return 0;
}