代码-CF863F Almost Permutation

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
#define x first
#define y second
#define bg begin()
#define ed end()
#define pb push_back
#define mp make_pair
#define sz(a) int((a).size())
#define R(i,n) for(int i(0);i<(n);++i)
#define L(i,n) for(int i((n)-1);~i;--i)
const int iinf=0x3f3f3f3f;
const ll linf=0x3f3f3f3f3f3f3f3f;

//Data
const int N=50;
int n,m,lv[N],rv[N];

//Flows
const int fN=N*2+2;
int fn,s,t;
vector<int> e[fN],to,fw,co;
void adde(int u,int v,int w,int c){
    // cout<<u<<" "<<v<<" "<<w<<" "<<c<<'\n';
    e[u].pb(sz(to)),to.pb(v),fw.pb(w),co.pb(+c);
    e[v].pb(sz(to)),to.pb(u),fw.pb(0),co.pb(-c);
}
int pre[fN],dep[fN];
bool vis[fN];
queue<int> q;
bool spfa(){
    R(u,fn) pre[u]=-1,dep[u]=iinf,vis[u]=false;
    q.push(pre[s]=s),dep[s]=0,vis[s]=true;
    while(sz(q)){
        int u=q.front(); q.pop(),vis[u]=false;
        for(int v:e[u])if(fw[v]&&dep[to[v]]>dep[u]+co[v])
            dep[to[v]]=dep[u]+co[v],pre[to[v]]=v,
            (!vis[to[v]])&&(q.push(to[v]),vis[to[v]]=true);
    }
    return dep[t]^iinf;
}
pair<int,int> flow(){
    pair<int,int> res(0,0);
    while(spfa()){
        int f=iinf;
        for(int u=t;u^s;u=to[pre[u]^1])
            f=min(f,fw[pre[u]]);
        for(int u=t;u^s;u=to[pre[u]^1])
            fw[pre[u]]-=f,fw[pre[u]^1]+=f;
        res.x+=f,res.y+=dep[t]*f;
    }
    return res;
}

//Main
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    cin>>n>>m,fn=(t=(s=n<<1)+1)+1;
    R(i,n) lv[i]=0,rv[i]=n-1;
    R(i,m){
        int o,l,r,v; cin>>o>>l>>r>>v,--v,--o,--l;
        R(j,r-l)if(o) rv[l+j]=min(rv[l+j],v);
            else lv[l+j]=max(lv[l+j],v);
    }
    R(i,n)if(lv[i]>=++rv[i]) cout<<-1<<'\n',exit(0);
    R(i,n){
        adde(s,i,1,0);
        R(j,rv[i]-lv[i]) adde(i,j+lv[i]+n,1,0);
        R(j,n) adde(i+n,t,1,2*j+1);
    } 
    cout<<flow().y<<'\n';
    return 0;
}