Submission #1057234

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057234		mindiyak	Love Polygon (BOI18_polygon)	C++14	0 / 100	794 ms	16232 KiB

polygon

#pragma GCC optimize("O1,O2,O3,Ofast,unroll-loops")
#include <bits/stdc++.h>
#include <string>
#include <iostream>
#include <cmath>
#include <numeric>
#include <stack>
#include <queue>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ld, ld> pd;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<vector<int>> vvi;
typedef vector<vector<pi>> vvpi;
typedef vector<ld> vd;
typedef vector<long long> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
#define FOR(i, a, b) for (int i = a; i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i, a, b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i, a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto &a : x)
#define uid(a, b) uniform_int_distribution<int>(a, b)(rng)
#define len(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define F first
#define nl endl
#define S second
#define lb lower_bound
#define ub upper_bound
#define aint(x) x.begin(), x.end()
#define raint(x) x.rbegin(), x.rend()
#define ins insert
const int M = 1e9+7;
void init(string name)
{
    freopen((name + ".in").c_str(), "r", stdin);
    freopen((name + ".out").c_str(), "w", stdout);
}
void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
}

int n;
map <string,int> arr;
vvi paths(1e5+10,vi());
int cnt = 0;
vi visited(1e5+10,0);
int len = 0;

int add_to(string a){
    if(arr.count(a)>0){
        return arr[a];
    }else{
        arr[a] = cnt;
        cnt ++;
        return cnt-1;
    }
}

void dfs(int pos){
    if(visited[pos])return;
    visited[pos] = 1;
    len ++;

    if(paths[pos].size() > 1)dfs(paths[pos][0]);
    // for(int a:paths[pos])dfs(a);
}
 
void solve()
{
    cin >> n;
    FOR(i,0,n){
        string a,b;
        cin >> a >> b;
        int c = add_to(a),d= add_to(b);
        paths[c].pb(d);
        cerr << c << " -> " << d << endl;
    }
    
    if(cnt%2 == 1){
        cout << -1 << endl;
        return;
    }

    int ones = 0,ans = 0;

    FOR(i,0,cnt){
        len = 0;
        dfs(i);
        cerr << i << " " << len << endl;
        ones += (len%2);
        ans += len/2;
    }
    cerr << "ones " << ones << endl;
    ans += ones;

    cout << ans << endl;
}   
 
 
int main()
{
    fastIO();
    // init("test");
    int t = 1;
    // cin >> t;
    while (t--)
        solve();
    return 0;
}

Compilation message (stderr)

polygon.cpp: In function 'void init(std::string)':
polygon.cpp:44:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |     freopen((name + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
polygon.cpp:45:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |     freopen((name + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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