标记当前区间是否完全相等

#include<bits/stdc++.h>
#define rep(ii,a,b) for(int ii=a;ii<=b;++ii)
#define ll long long
using namespace std;
const int maxn=1e5+10,maxm=sqrt(1e5+1)+10;
int n,m;
ll a[maxn],b[maxn];
class sqblock{public:
  int id[maxn],sz,cnt;
  struct block{int l,r;ll sum,taga,tagb;}node[maxm];
  void pushdown(int now){
    block &nd=node[now];
    if(nd.taga) rep(i,nd.l,nd.r) a[i]=nd.taga;
    nd.taga=0;
  }
  void init(int n){
    sz=sqrt(n+0.5);
    rep(i,1,n) id[i]=(i-1)/sz+1;cnt=id[n];
    rep(i,1,cnt) node[i].l=(i-1)*sz+1;
    rep(i,1,cnt-1) node[i].r=i*sz;
    node[cnt].r=n;
  }
  void update(int s,int t,ll x){
    int posl=id[s],posr=id[t];
    pushdown(posl);pushdown(posr);
    if(posl==posr){
      rep(i,s,t) {
        node[posl].sum+=abs(a[i]-x);
        b[i]+=abs(a[i]-x);
        a[i]=x;
      }
      return ;
    }
    rep(i,s,node[posl].r){
      b[i]+=abs(a[i]-x);
      node[posl].sum+=abs(a[i]-x);
      a[i]=x;
    }
    rep(i,node[posr].l,t){
      b[i]+=abs(a[i]-x);
      node[posr].sum+=abs(a[i]-x);
      a[i]=x;
    }
    rep(i,posl+1,posr-1){
      if(node[i].taga){
        node[i].tagb+=abs(x-node[i].taga);
        node[i].sum+=1ll*abs(x-node[i].taga)*(node[i].r-node[i].l+1);
        node[i].taga=x;
      }else {
        rep(j,node[i].l,node[i].r){
          b[j]+=abs(a[j]-x);
          node[i].sum+=abs(a[j]-x);
          a[j]=x;
        }
        node[i].taga=x;
      }
    }
    
  }
  ll query(int s,int t){
    int posl=id[s],posr=id[t];ll ans=0;
    if(posl==posr) {
      rep(i,s,t) ans+=b[i]+node[posl].tagb;
      return ans;
    }
    rep(i,s,node[posl].r) ans+=b[i]+node[posl].tagb;
    rep(i,node[posr].l,t) ans+=b[i]+node[posr].tagb;
    rep(i,posl+1,posr-1) ans+=node[i].sum;
    return ans;
  }
}square;
int main() {ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
  cin>>n>>m;
  rep(i,1,n) a[i]=i;
  square.init(n);
  int a,b,c;
  while(m--){
    cin>>a;
    if(a==1){
      cin>>a>>b>>c;
      square.update(a,b,c);
    }else {
      cin>>a>>b;
      cout<<square.query(a,b)<<'\n';
    }
  }
}