제출 #366882

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
366882		ACmachine	Love Polygon (BOI18_polygon)	C++17	46 / 100	1167 ms	14496 KiB

polygon

#include <bits/stdc++.h>
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back 
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize 
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
	
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif

#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}        
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}

   
struct dsu{
    vector<int> e;
    dsu(){};
    dsu(int n){
        e.resize(n, -1);
    }
    int find(int x){ return (e[x] < 0 ? x : e[x] = find(e[x])); }
    int size(int x){ return -e[find(x)]; }
    int sameSet(int a, int b){ return find(a) == find(b); }
    bool join(int a, int b){
        a = find(a); b = find(b);
        if(a == b) return false;
        if(e[a] > e[b]) swap(a, b);
        e[a] += e[b]; e[b] = a;
        return true;
    }
};
int solve_dp(vector<int> &g, int n){
    vector<vi> mat(n, vi(n));
    REP(i, n) mat[i][g[i]] = 1;
    vi dp((1 << n), INF);
    dp[0] = 0; 
    REP(mask, (1 << n)){
        REP(i, n){
            REP(j, n){
                if(i == j) continue;
                if(!(mask & (1 << i)) && !(mask &(1 << j))){
                    dp[mask|(1 << i)|(1 << j)] = min(dp[mask|(1 << i)|(1 << j)], dp[mask] + (2 - mat[i][j] - mat[j][i]));
                }
            }
        }
    }
    return dp[(1 << n) - 1];
}
int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
	int n; cin >> n;
    if(n % 2 == 1){
        cout << -1 << "\n";
        return 0;
    }
    vector<int> g(n);
    int curr_id = 0;
    map<string, int> name_to_id;
    REP(i, n){
        string s, t;
        cin >> s >> t;
        int u, v;
        if(name_to_id.find(s) == name_to_id.end())
            name_to_id[s] = curr_id++;
        if(name_to_id.find(t) == name_to_id.end())
            name_to_id[t] = curr_id++;
        u = name_to_id[s];
        v = name_to_id[t];
        g[u] = v;
    }
    if(n <= 20){
        cout << solve_dp(g, n) << "\n";
        return 0;
    }
    vector<int> cycle_begins;
    vector<int> visited(n, -1);
    function<void(int, int, bool)> dfs = [&](int v, int id, bool cycle_finding){
        visited[v] = id;
        if(visited[g[v]] == -1) 
            dfs(g[v], id, cycle_finding);
        else{
            if(visited[g[v]] == visited[v] && cycle_finding)
                cycle_begins.pb(v);
        }
    };
    int cid = 0;
    REP(i, n){
        if(visited[i] == -1){
            dfs(i, cid, true);
            cid++;
        }
    }
    fill(all(visited), -1);
    cid = 0;
    REP(i, cycle_begins.size()){
        if(visited[cycle_begins[i]] == -1){
            dfs(cycle_begins[i], cid, false); 
            cid++;
        }
    }
    int cycle_ids = cid;
    vector<int> chain_begins;
    vector<int> indeg(n, 0);
    REP(i, n){
        indeg[g[i]]++; 
    }
    REP(i, n){
        if(indeg[i] == 0) chain_begins.pb(i);
    }
    int res = 0; // sekame chainy
    vector<bool> used(n, false);
    function<void(int)> dfs2 = [&](int v){
        if(!used[v] && !used[g[v]] && v != g[v]){
            res++;
            used[v] = used[g[v]] = true;
        }
        if(visited[g[v]] == -1){
            dfs2(g[v]);
        }
    };
    for(int st : chain_begins){
        dfs2(st);
    }
    dsu d(n); 
    REP(i, n){
        if(!used[i]){
            if(!used[g[i]]){
                if(g[g[i]] == i && i != g[i]){
                    used[i] = used[g[i]] = true;
                    continue;
                }
                d.join(i, g[i]);
            }
        }
    }
    REP(i, n){
        if(!used[i]){
            if(d.find(i) == i){
                int sz = d.size(i);
                if(sz % 2 == 1) res += sz / 2 + 1;
                else res += sz / 2;
            }
        }
    }
    cout << res << "\n";
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

polygon.cpp: In function 'int main()':
polygon.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
      |                                        ^
polygon.cpp:28:18: note: in expansion of macro 'FOR'
   28 | #define REP(i,b) FOR(i,0,b,1)
      |                  ^~~
polygon.cpp:166:5: note: in expansion of macro 'REP'
  166 |     REP(i, cycle_begins.size()){
      |     ^~~
polygon.cpp:172:9: warning: unused variable 'cycle_ids' [-Wunused-variable]
  172 |     int cycle_ids = cid;
      |         ^~~~~~~~~

• Subtask 1: 21 / 21
• Subtask 2: 25 / 25
• Subtask 3: 0 / 29
• Subtask 4: 0 / 25