我花了近一个小时编了这个程序，结果却是……

#include<bits/stdc++.h>
using namespace std;
const int maxn=5000000;
int a[maxn],tree[4*maxn],n,m,x,y,k,v,setv[maxn],t;
char op;
void news(int o,int l,int r){
	tree[o]=tree[o*2]|tree[o*2+1];
	if(setv[o]>0)tree[o]=setv[o];
}
void down(int o){
	if(setv[o]>0){
		setv[o*2]=setv[o*2+1]=setv[o];
		setv[o]=0;
	}
}

void built(int o,int l,int r){
	if(l==r){
		tree[o]=setv[o]=1;
		return;
	}
	int m=(l+r)/2;
	built(o*2,l,m);
	built(o*2+1,m+1,r);
	news(o,l,r);
}
void chaxun(int o,int l,int r){
	if(x<=l&&r<=y){
		setv[o]=1<<v-1;
		tree[o]=1<<v-1;
		return;
	}
	down(o);
	int m=(l+r)/2;
	if(x<=m)chaxun(o*2,l,m);else news(o*2,l,m);
	if(y>m) chaxun(o*2+1,m+1,r);else news(o*2+1,m+1,r);
	news(o,l,r);
}
int he(int o,int l,int r){
	if(setv[o]>0){
		return setv[o];
	}
	if(x<=l&&r<=y){
		return tree[o];
	}
	int m=(l+r)/2,ans=0;
	if(x<=m)ans=ans|he(o*2,l,m);
	if(y>m)ans=ans|he(o*2+1,m+1,r);
	return ans;
}
int main(){
	freopen("tree.in","r",stdin);
	scanf("%d%d%d",&n,&t,&m);
	built(1,1,n);
	for(int i=1;i<=m;i++){
		scanf("%c",&op);
		if(op=='C'){
			cin>>x>>y>>v;
			if(x>y)swap(x,y);
			chaxun(1,1,n);
		}
		else{
			cin>>x>>y;
			if(x>y)swap(x,y);
			int t=he(1,1,n);
			int ans=0;
			while(t){
				ans+=t%2;
				t/=2;
			}
			printf("%d",&ans);
		}
	}
	return 0;
}