제출 #171463

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
171463		VEGAnn	관광지 (IZhO14_shymbulak)	C++14	0 / 100	1558 ms	10104 KiB

shymbulak

#include <bits/stdc++.h>
#define all(x) x.begin(),x.end()
#define sz(x) ((int)x.size())
#define PB push_back
#define MP make_pair
#define ft first
#define sd second
#define pll pair<ll, ll>
#define pii pair<int, int>
using namespace std;
typedef long long ll;
const ll OO = 1e18;
const int oo = 2e9;
const int N = 200100;
const int M = 1010;
vector<int> g[N], vc, cyc;
set<pii> st;
bool in_cyc[N];
int n, ans = 0, dst[N], mx = 0, mrk[N];

void CYCLE(int lst){
    cyc.clear();
    int it = sz(vc) - 1;
    while (1){
        cyc.PB(vc[it]);
        in_cyc[vc[it]] = 1;
        if (vc[it] == lst)
            break;
        it--;
    }
}

void dfs(int v, int p){
    if (sz(cyc) > 0) return;
    vc.PB(v);
    mrk[v] = 1;
    for (int u : g[v]){
        if (u == p) continue;
        if (mrk[u] == 0)
            dfs(u, v); else
        if (mrk[u] == 1)
            CYCLE(u);
    }
    mrk[v] = 2;
    vc.pop_back();
}

int main(){
    cin >> n;
    for (int i = 0; i < n; i++){
        int x, y; cin >> x >> y;
        x--; y--;
        g[x].PB(y); g[y].PB(x);
    }
    dfs(0, -1);
    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++) {
            dst[j] = oo;
            mrk[j] = 0;
        }
        dst[i] = 0;
        st.insert(MP(0, i));
        while (sz(st)){
            int v = (*st.begin()).sd;
            mrk[v] |= in_cyc[v];
            st.erase(st.begin());
            for (int u : g[v])
                if (dst[u] > dst[v] + 1){
                    st.erase(MP(dst[u], u));
                    mrk[u] = mrk[v];
                    dst[u] = dst[v] + 1;
                    st.insert(MP(dst[u], u));
                }
        }
        for (int v = 0; v < n; v++) {
            if (dst[v] > mx) {
                mx = dst[v];
                ans = 0;
            }
            if (dst[v] == mx)
                ans += ((sz(cyc) % 2 == 0 && mrk[v]) ? 2 : 1);
        }
    }
    cout << ans / 2;
    return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 20
• Subtask 3: 0 / 50