Submission #173367

#	Time	Username	Problem	Language	Result	Execution time	Memory
173367		achibasadzishvili	Hard route (IZhO17_road)	C++14	0 / 100	13 ms	12152 KiB

road

#include<bits/stdc++.h>
#define ll long long
#define f first
#define s second
#define pb push_back
#define N 500005
using namespace std;
ll pp[N],n,cur,ind,cen;
vector<ll>v[N];
pair<ll,ll>mx[N];
ll ans,ansraod;
void dfs(ll x,ll par,ll dep){
    pp[x] = par;
    if(dep > cur){
        ind = x;
        cur = dep;
    }
    for(int i=0; i<v[x].size(); i++)
        if(v[x][i] != par)
            dfs(v[x][i] , x , dep + 1);
}
void go(ll x,ll par){
    mx[x].f = 0;
    mx[x].s = 1;
    for(int i=0; i<v[x].size(); i++)
        if(v[x][i] != par){
            int to = v[x][i];
            go(to , x);
            if(mx[to].f > mx[x].f){
                mx[x].f = mx[to].f;
                mx[x].s = 0;
            }
            if(mx[to].f == mx[x].f)
                mx[x].s += mx[to].s;
        }
    mx[x].f++;
}
void solve(ll x,ll par,ll zed){
    ll mx1 = -1,mx2 = -1,ind = 0;
    for(int i=0; i<v[x].size(); i++)
        if(v[x][i] != par){
            int to = v[x][i];
            if(mx[to].f >= mx1){
                ind = to;
                mx2 = mx1;
                mx1 = mx[to].f;
            }
            else if(mx[to].f > mx2)mx2 = mx[to].f;
        }
    mx1++;
    mx2++;
    for(int i=0; i<v[x].size(); i++)
        if(v[x][i] != par){
            int to = v[x][i];
            ll nex = 0;
            if(to == ind)
                nex = max(zed + 1 , mx2);
            else nex = max(zed + 1 , mx1);
            solve(to , x , nex);
        }
    mx1 = -1,mx2 = -1;
    ll ra1 = -1 , ra2 = 0 , raod = 0 , sum = 0 , minus = 0 , in = 0;
    for(int i=0; i<v[x].size(); i++){
        if(v[x][i] != par){
            int to = v[x][i];
            if(mx[to].f == mx[x].f - 1){
                sum += mx[to].s;
                minus += (mx[to].s - 1) * mx[to].s / 2 + mx[to].s;
                raod++;
                in = to;
            }
        }
    }
    if(raod > 1){
        ll namr = zed;
        if(namr * 2LL * (mx[x].f - 1) > ans){
            ans = namr * 2LL * (mx[x].f - 1);
            ansraod = 0;
        }
        if(namr * 2LL * (mx[x].f - 1) == ans){
            ansraod += (sum * sum - minus) / 2;
        }
        return;
    }
    for(int i=0; i<v[x].size(); i++){
        if(v[x][i] != par){
            int to = v[x][i];
            if(to == in)continue;
            if(mx[to].f > ra1){
                ra1 = mx[to].f;
                ra2 = 0;
            }
            if(mx[to].f == ra1){
                ra2 += mx[to].s;
            }
        }
    }
    ll namr = zed;
    if(namr * (mx[x].f - 1 + ra1) > ans){
        ans = namr * (mx[x].f - 1 + ra1);
        ansraod = 0;
    }
    if(namr * (mx[x].f - 1 + ra1) == ans){
        ansraod += sum * ra2;
    }
}
int main(){
    ios::sync_with_stdio(false);
    cin >> n;
    
    if(n == 2){
        cout << 0 << " " << 1 << '\n';
        return 0;
    }
    
    for(int i=1; i<n; i++){
        int x,y;
        cin >> x >> y;
        v[x].pb(y);
        v[y].pb(x);
    }
    
    ind = 1;
    cur = 0;
    dfs(1 , 0 , 0);
    cur = 0;
    dfs(ind , 0 , 0);
    ll we = cur;
    cur = cur / 2;
    
    cen = ind;
    while(cur--){
        cen = pp[cen];
    }
    if(we % 2 == 0){
        go(cen , 0);
        solve(cen , 0 , 0);
        ll x = cen;
        ll gan = 0 , sum = 0 , minus = 0;
        for(int i=0; i<v[x].size(); i++)
            if(v[x][i] != 0){
                int to = v[x][i];
                if(mx[to].f == mx[x].f - 1){
                    gan++;
                    sum += mx[to].s;
                    minus += (mx[to].s - 1) * mx[to].s / 2 + mx[to].s;
                    continue;
                }
            }
        if(gan > 2){
        ll namr = max(mx[x].f - 1 , 0LL);
        if(namr * 2LL * (mx[x].f - 1) > ans){
            ans = namr * 2LL * (mx[x].f - 1);
            ansraod = 0;
        }
        if(namr * 2LL * (mx[x].f - 1) == ans){
            ansraod += (sum * sum - minus) / 2;
        }
        }
        cout << ans << " " << ansraod << '\n';
        return 0;
    }
    go(cen , pp[cen]);
    go(pp[cen] , cen);
    solve(cen , pp[cen] , mx[pp[cen]].f);
    solve(pp[cen] , cen , mx[cen].f);
    
    
    
    cout << ans << " " << ansraod << '\n';
    
    
    return 0;
}

Compilation message (stderr)

road.cpp: In function 'void dfs(long long int, long long int, long long int)':
road.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v[x].size(); i++)
                  ~^~~~~~~~~~~~
road.cpp: In function 'void go(long long int, long long int)':
road.cpp:25:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v[x].size(); i++)
                  ~^~~~~~~~~~~~
road.cpp: In function 'void solve(long long int, long long int, long long int)':
road.cpp:40:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v[x].size(); i++)
                  ~^~~~~~~~~~~~
road.cpp:52:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v[x].size(); i++)
                  ~^~~~~~~~~~~~
road.cpp:63:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v[x].size(); i++){
                  ~^~~~~~~~~~~~
road.cpp:85:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v[x].size(); i++){
                  ~^~~~~~~~~~~~
road.cpp: In function 'int main()':
road.cpp:140:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0; i<v[x].size(); i++)
                      ~^~~~~~~~~~~~

• Subtask 1: 0 / 19
• Subtask 2: 0 / 33
• Subtask 3: 0 / 48