一道线段树。lazy标记+位运算……（第一次写这个什么lazy标记，抄了一发题解）

我们发现：“或”操作在这里用正合适。
原题请戳这里

// by Sirius_Ren
#include <cstdio>
#include <algorithm>
#define N 100010
using namespace std;
int l,t,o,xx,yy,zz;
char jy;
struct segtree{int left,right,num,lazy;}tree[N*4];
void build(int l,int r,int pos){tree[pos].left=l,tree[pos].right=r,tree[pos].num=2,tree[pos].lazy=false;if(l==r)return;int mid=(l+r)/2;build(l,mid,pos*2),build(mid+1,r,pos*2+1);
}
void push_down(int pos){tree[pos*2].lazy=tree[pos*2+1].lazy=true;tree[pos*2+1].num=tree[pos*2].num=tree[pos].num;tree[pos].lazy=false;
}
void add(int pos){if(tree[pos].left>=xx&&tree[pos].right<=yy){tree[pos].lazy=true;tree[pos].num=(1<<zz);return;}if(tree[pos].lazy)push_down(pos);int mid=(tree[pos].left+tree[pos].right)/2;if(xx<=mid)add(pos*2);if(yy>mid)add(pos*2+1);tree[pos].num=tree[pos*2].num|tree[pos*2+1].num;
}
int query(int pos){if(tree[pos].left>=xx&&tree[pos].right<=yy)return tree[pos].num;if(tree[pos].lazy)push_down(pos);int mid=(tree[pos].left+tree[pos].right)/2;if(xx>mid)return query(pos*2+1);else if(yy<=mid)return query(pos*2);else return query(pos*2+1)|query(pos*2);
}
int split(){int sum=query(1),ans=0;while(sum/=2)if(sum%2)ans++;return ans;
}
int main()
{scanf("%d%d%d",&l,&t,&o);build(1,l,1);for(int i=1;i<=o;i++){scanf("\n%c%d%d",&jy,&xx,&yy);if(xx>yy)swap(xx,yy);if(jy=='C')scanf("%d",&zz),add(1);else printf("%d\n",split());}
}

晚上又写了一遍
很可惜，只刷到了Code Length第三… 省了一步建树。

#include <bitset>
#include <cstdio>
#include <algorithm>
using namespace std;
int L,o,xx=1,yy,zz=1,t[400001];
char jy;
bitset<400001>B;
void pd(int p){t[p*2]=t[p*2+1]=t[p];B[p*2]=B[p*2+1]=true;B[p]=false;}
void add(int l,int r,int p){if(l>=xx&&r<=yy){B[p]=1;t[p]=1<<zz-1;return;}if(B[p])pd(p);int m=(l+r)/2;if(xx<=m)add(l,m,p*2);if(yy>m)add(m+1,r,p*2+1);t[p]=t[p*2]|t[p*2+1];
}
int q(int l,int r,int p){if(xx<=l&&yy>=r)return t[p];if(B[p])pd(p);int m=(l+r)/2;if(m<xx)return q(m+1,r,p*2+1);else if(m>=yy)return q(l,m,p*2);else return q(l,m,p*2)|q(m+1,r,p*2+1);
}
int main(){scanf("%d%d%d",&L,&jy,&o);yy=L,add(1,L,1);while(o--){scanf("\n%c%d%d",&jy,&xx,&yy);if(xx>yy)swap(xx,yy);if(jy=='C')scanf("%d",&zz),add(1,L,1);else{int s=q(1,L,1),a=0;while(s){if(s%2)a++;s/=2;}printf("%d\n",a);}}
}