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Submission #434010

# Submission time Handle Problem Language Result Execution time Memory
434010 2021-06-20T13:45:15 Z HediChehaidar Love Polygon (BOI18_polygon) C++17
75 / 100
 337 ms 18988 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];
bool rel[(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);
        if(adj[adj[i][0]][0] == i && adj[i][0] != i){
            rel[i] = true;
            rel[adj[i][0]] = true;
        }
    }
    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] || rel[pos]) continue;
        vis[pos] = true;
        int c = adj[pos][0];
        if(!rel[c])
            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
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2764 KB Output is correct
2 Correct 2 ms 2764 KB Output is correct
3 Correct 2 ms 2764 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2764 KB Output is correct
8 Correct 2 ms 2764 KB Output is correct
9 Correct 3 ms 2684 KB Output is correct
10 Correct 2 ms 2764 KB Output is correct
11 Correct 2 ms 2764 KB Output is correct
12 Correct 2 ms 2764 KB Output is correct
13 Correct 2 ms 2764 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2636 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2764 KB Output is correct
2 Correct 2 ms 2764 KB Output is correct
3 Correct 2 ms 2764 KB Output is correct
4 Correct 337 ms 18364 KB Output is correct
5 Correct 268 ms 14440 KB Output is correct
6 Correct 288 ms 18988 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 263 ms 14516 KB Output is correct
2 Correct 255 ms 15176 KB Output is correct
3 Correct 201 ms 14264 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 279 ms 16144 KB Output is correct
6 Correct 245 ms 14240 KB Output is correct
7 Correct 249 ms 14332 KB Output is correct
8 Correct 219 ms 14244 KB Output is correct
9 Correct 219 ms 14344 KB Output is correct
10 Correct 179 ms 14276 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 2764 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 2 ms 2764 KB Output is correct
2 Correct 2 ms 2764 KB Output is correct
3 Correct 2 ms 2764 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2764 KB Output is correct
8 Correct 2 ms 2764 KB Output is correct
9 Correct 3 ms 2684 KB Output is correct
10 Correct 2 ms 2764 KB Output is correct
11 Correct 2 ms 2764 KB Output is correct
12 Correct 2 ms 2764 KB Output is correct
13 Correct 2 ms 2764 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2636 KB Output is correct
16 Correct 2 ms 2764 KB Output is correct
17 Correct 2 ms 2764 KB Output is correct
18 Correct 2 ms 2764 KB Output is correct
19 Correct 337 ms 18364 KB Output is correct
20 Correct 268 ms 14440 KB Output is correct
21 Correct 288 ms 18988 KB Output is correct
22 Correct 2 ms 2636 KB Output is correct
23 Correct 263 ms 14516 KB Output is correct
24 Correct 255 ms 15176 KB Output is correct
25 Correct 201 ms 14264 KB Output is correct
26 Correct 2 ms 2636 KB Output is correct
27 Correct 279 ms 16144 KB Output is correct
28 Correct 245 ms 14240 KB Output is correct
29 Correct 249 ms 14332 KB Output is correct
30 Correct 219 ms 14244 KB Output is correct
31 Correct 219 ms 14344 KB Output is correct
32 Correct 179 ms 14276 KB Output is correct
33 Correct 2 ms 2636 KB Output is correct
34 Correct 2 ms 2764 KB Output is correct
35 Correct 2 ms 2764 KB Output is correct
36 Correct 2 ms 2636 KB Output is correct
37 Correct 328 ms 16448 KB Output is correct
38 Incorrect 294 ms 17352 KB Output isn't correct
39 Halted 0 ms 0 KB -