This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pb push_back
using namespace std;
int k,n;ll re=0;
map<ll,int>st,en;
ll no=0,fin=0;vector<pair<ll,ll>>v;
int main()
{
    cin>>k>>n;ll w=0;
    for(int i=0;i<n;i++)
    {
        char a,b;
        int x,y;
        cin>>a>>x>>b>>y;
        re+=abs(x-y);
        if(a==b)continue;
        re++;
        if(x>y)swap(x,y);
        v.pb({x,y});
        st[x]++;st[x+1];st[x-1];st[y+1];st[y-1];
        st[y];no++;
        en[y]++;w+=x;
    }
    ll mn=1e17;
    ll last=0;
    for(auto it:st)
    {if(it.fi<0)continue;
        ll z=0;
        for(auto ff:v)
        {
            if(ff.fi<=it.fi&&ff.se>=it.fi)continue;
            ll u=min(abs(ff.fi-it.fi),abs(ff.se-it.fi));
            u*=2;
            z+=u;
        }
        mn=min(mn,z);
        /*
        w+=fin*(it.fi-last);
        w-=no*(it.fi-last);
        fin+=en[it.fi];
        no-=st[it.fi];
        mn=min(mn,w);last=it.fi;
    */}
    re+=mn;
    cout<<re;
}
Compilation message (stderr)
bridge.cpp: In function 'int main()':
bridge.cpp:28:8: warning: unused variable 'last' [-Wunused-variable]
   28 |     ll last=0;
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