Submission #999251

#	Time	Username	Problem	Language	Result	Execution time	Memory
999251		vjudge1	LOSTIKS (INOI20_lostiks)	C++17	0 / 100	2037 ms	29188 KiB

Main

#include <bits/stdc++.h>
//#define int ll
#define MAX 1000001
#define INF INT_MAX
#define MOD 1000000007
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ins insert
#define ff first
#define ss second 
#define all(a) a.begin(),a.end()
#define lb(a,b) lower_bound(all(a),b)
#define ub(a,b) upper_bound(all(a),b)
#define sortv(a) sort(all(a))
#define outputar(a,b){\
    for(int i=0;i<b;i++){\
        cout << a[i] << " ";\
    }\
    cout << endl;\
}
#define outputvec(a){\
    for(auto x:a){\
        cout << (int)x << " ";\
    }\
    cout << endl;\
}
#define reset(a,n,v){\
    for(int i=0;i<n;i++){\
        a[i]=v;\
    }\
}
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef tuple<ll,ll,ll> tll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef double db;
typedef long double ldb;
inline void USACO(string filename){
  freopen((filename+".in").c_str(),"r",stdin);
  freopen((filename+".out").c_str(),"w",stdout);
}
int n,q,t=1,m,k,x,y,z,x2,y2,z2,a[MAX],b[MAX],d[MAX];
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//string s[MAX],str[MAX];
//int e[1001][1001];
string s1,s2,s3;
const int mod = 998244353;
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
vector<vector<int>> g;
int st[MAX][20],dep[MAX],pre[MAX],cnt=0;
int lca(int x,int y){
    if(dep[x]<dep[y]){
        swap(x,y);
    }
    int h=dep[x]-dep[y];
    for(int i=0;i<20;i++){
        if((h&(1<<i))){
            x=st[x][i];
        }
    }
    if(x==y){
        return x;
    }
    for(int i=19;i>=0;i--){
        if(st[x][i]!=st[y][i]){
            x=st[x][i];
            y=st[y][i];
        }
    }
    return pre[x];
}
void dfs(int v,int prev){
    st[v][0]=prev;
    pre[v]=prev;
    for(auto x:g[v]){
        if(x==prev){
            continue;
        }
        dep[x]=dep[v]+1;
        dfs(x,v);
    }
}
void solve(){
    cin >> n;
    g.clear();
    g.resize(n+1);
    cin >> m >> k; 
    vector<array<int,3>> c;
    for(int i=0;i<n-1;i++){
        cin >> x >> y >> z;
        g[x].pb(y);
        g[y].pb(x);
        a[i]=z;
        if(a[i]!=0){
            c.pb({x,y,i});
            cnt++;
        }
    }
    dfs(1,-1);
    for(int i=1;i<20;i++){
        for(int j=1;j<=n;j++){
            if(st[j][i-1]!=-1){
                st[j][i]=st[st[j][i-1]][i-1];
            }
        }
    }
    for(int i=0;i<cnt;i++){
        int n1,n2; 
        n1=c[0][0];
        n2=c[0][1];
        if(dep[n1]<dep[n2]){
            swap(n1,n2);
        }
        c.pb({n1,n2,c[0][2]});
        c.erase(c.begin());
    }
    int res=INF; 
    do{
        for(auto x:c){
            b[x[2]]=0;
            d[x[2]]=0;
        }
        int res1=0;
        int h,h1,h2;
        h=m;
        h2=0;
        int cnt1=1,cnt2=0;
        set<array<int,3>> e;
        h1=lca(m,k);
        for(auto x:c){
            int h3,h4; 
            h3=lca(x[0],m);
            h4=lca(x[0],k);
            if((h3==x[0] && dep[h3]>dep[h1]) || (h4==x[0] && dep[h4]>dep[h1])){
                e.ins({cnt1,cnt-cnt2,x[2]});
                d[x[2]]=cnt1;
            }
            cnt2++;
        }
        int cnt3=0;
        while(e.size()>0){
            cnt1++;
            cnt2=0;
            bool ok=false; 
            array<int,3> p=*(--e.end());
            h1=lca(a[p[2]],h);
            for(auto x:c){
                if(b[x[2]]==1){
                    continue;
                }
                int h3,h4; 
                h3=lca(x[0],a[p[2]]);
                h4=lca(x[0],h);
                if((h3==x[0] && dep[h3]>dep[h1]) || (h4==x[0] && dep[h4]>dep[h1])){
                    if(d[x[2]]!=0){
                        e.erase({d[x[2]],cnt-cnt2,x[2]});
                    }
                    e.ins({cnt1,cnt-cnt2,x[2]});
                    ok=true;
                }
                cnt2++;
            }
            if(!ok){
                res1+=dep[h]+dep[a[p[2]]]-2*dep[h1];
                e.erase(p);
                b[p[2]]=1;
                h=a[p[2]];
            }
            if(cnt3==100){
                res1=INF;
                break;
            }
            cnt3++;
        }
        if(res1!=INF){
            h1=lca(h,k); 
            res1+=dep[h]+dep[k]-2*dep[h1];
        }
        res=min(res,res1);
    }while(next_permutation(all(c)));
    if(res==INF){
        res=-1;
    }
    cout << res << "\n";
}
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    //freopen("input13.txt","r",stdin);
    //cin >> t;
    ll cnt1=1;
    while(t--){
        solve();
        cnt1++; 
    }
}

Compilation message (stderr)

Main.cpp: In function 'void solve()':
Main.cpp:128:18: warning: variable 'h2' set but not used [-Wunused-but-set-variable]
  128 |         int h,h1,h2;
      |                  ^~

• Subtask 1: 0 / 23
• Subtask 2: 0 / 36
• Subtask 3: 0 / 41