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Submission #434001

# Submission time Handle Problem Language Result Execution time Memory
434001 2021-06-20T13:34:19 Z HediChehaidar Love Polygon (BOI18_polygon) C++17
29 / 100
 312 ms 16072 KB 
/*
ID: hedichehaidar
TASK: photo
LANG: C++11
*/
#include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double db;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);} // least common multiple (PPCM)
#define ss second
#define ff first
#define all(x) (x).begin() , (x).end()
#define pb push_back
#define vi vector<int>
#define vii vector<pair<int,int>>
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd  pair<double,double>
#define vdd  vector<pdd>
#define dte  tuple<double , double , double>
using namespace std;
const int INF = 1000*1000*1000; // 1 e 9
const int MOD = INF + 7;
const double EPS = 0.000000001; // 1 e -9
const ll inf = (ll)1e18;

int n;
map<string  , int> m;
vi adj[(int)1e5 + 10];
bool vis[(int)1e5 + 10];
vi ts;
void dfs(int pos){
    if(vis[pos]) return ;
    vis[pos] = true;
    for(auto c : adj[pos]) dfs(c);
    ts.pb(pos);
}
int main() {
    //ifstream fin ("race.in");
    //ofstream fout ("race.out");
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    cin>>n;
    if(n % 2) return cout << -1 << endl,0;
    int cur = 0;
    for(int i = 0 ; i < n ; i++){
        string a , b ; cin>>a>>b;
        if(m.find(a) == m.end()){
            m[a] = cur; cur++;
        }
        if(m.find(b) == m.end()){
            m[b] = cur; cur++;
        }
        int u = m[a] , v = m[b];
        adj[u].pb(v);
    }
    for(int i = 0 ; i < n ; i++){
        if(!vis[i]) dfs(i);
    }
    reverse(all(ts));
    memset(vis , 0 , sizeof vis);
    int ans = 0;
    for(int i = 0 ; i < n ; i++){
        int pos = ts[i];
        if(vis[pos]) continue;
        vis[pos] = true;
        int c = adj[pos][0];
        vis[c] = true;
        ans++;
    }
    cout << ans << "\n";
    return 0;
}

/*
    Think of : BS / DFS / BFS / SSSP / SCC / MSP / MAX FLOW / TOPSORT / LCA / MATRIX / DP(bitmask) / 2 POINTERS / SEG TREE / MATH / UN FIND / MO
    Read the statement CAREFULLY !!
    Make a GREADY APPROACH !!!! (start from highest / lowest)
    Make your own TESTS !!
    Be careful from CORNER CASES !
*/

Subtask #1
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2784 KB Output is correct
2 Correct 3 ms 2764 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2764 KB Output is correct
5 Correct 2 ms 2608 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2764 KB Output is correct
8 Incorrect 2 ms 2636 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #2
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Incorrect 2 ms 2636 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 311 ms 14432 KB Output is correct
2 Correct 297 ms 15104 KB Output is correct
3 Correct 224 ms 14280 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 312 ms 16072 KB Output is correct
6 Correct 287 ms 14256 KB Output is correct
7 Correct 291 ms 14308 KB Output is correct
8 Correct 279 ms 14352 KB Output is correct
9 Correct 237 ms 14312 KB Output is correct
10 Correct 196 ms 14288 KB Output is correct
11 Correct 2 ms 2636 KB Output is correct
12 Correct 2 ms 2764 KB Output is correct
13 Correct 2 ms 2636 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct

Subtask #4
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2784 KB Output is correct
2 Correct 3 ms 2764 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2764 KB Output is correct
5 Correct 2 ms 2608 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2764 KB Output is correct
8 Incorrect 2 ms 2636 KB Output isn't correct
9 Halted 0 ms 0 KB -