Submission #612018

#	Time	Username	Problem	Language	Result	Execution time	Memory
612018		HediChehaidar	Simurgh (IOI17_simurgh)	C++17	0 / 100	31 ms	956 KiB

simurgh

#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 = 1e9 + 7;//998244353 ;
const double EPS = 0.000000001; // 1 e -9
const ll inf = (ll)1e18;

#include"simurgh.h"
/*int count_common_roads(vi v){
    cout << "req  ";
    for(auto c : v) cout << c << " "; cout << endl;
    int ans; cin>>ans; return ans;
}*/
int n , m;
vi adj[505];
set<vi> s;
int nb[505][505];
vi v , ans;
int q = 0;
void dfs(int pos , int mask){
    //cout << pos << " " << mask << "\n";
    if(pos == n){

        if(mask != (1 << n) - 1 || v.size() < n -  1) return ;
        vi vv = v; sort(all(vv)); if(s.find(vv) != s.end()) return ;
        s.insert(vv);
        int x = count_common_roads(v);
        if(x == n - 1) ans = v;
        return ;
    }
    int x = adj[pos].size();
    for(int i = 0 ; i < (1 << x) ; i++){
        int cur = i ? (1 << pos) : 0 ; bool ok = true;
        vi a;
        for(int j = 0 ; j < x ; j++){
            if((1 << j) & i){
                if(mask & (1 << adj[pos][j])){
                    ok = false; break;
                }
                cur += (1 << adj[pos][j]);
                a.pb(nb[pos][adj[pos][j]]);
            }
        }
        if(!ok) continue;
        for(auto c : a) v.pb(c);
        dfs(pos + 1 , mask | cur);
        for(int k = 0 ; k < a.size() ; k++) v.pop_back();
    }
}
vi find_roads(int N , vi a , vi b){
    n = N; m = a.size();
    if(n > 7) return ans;
    for(int i = 0 ; i < m ; i++){
        int x = a[i] , y = b[i];
        nb[x][y] = nb[y][x] = i;
        adj[x].pb(y); adj[y].pb(x);
    }
    dfs(0 , 0);
    return ans;
}

/*int main(){
    //ifstream fin ("testing.txt");
    //ofstream fout ("output.txt");
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int nn , mm; cin>>nn>>mm;
    vi a(mm) , b(mm); for(int i = 0 ; i < mm ; i++) cin>>a[i]>>b[i];
    for(auto c : find_roads(nn , a , b)) cout << c << " "; cout << "\n";
    return 0;
}*/
/*
4 6
0 1
0 2
0 3
1 2
1 3
2 3
*/
/*
    Think of : BS / DFS / BFS / SSSP / SCC / MSP / MAX FLOW / TOPSORT / LCA / MATRIX / DP(bitmask) / 2 POINTERS / SEG TREE / MATH / UN FIND / MO / HLD
    Read the statement CAREFULLY !!
    Make a GREADY APPROACH !!!! (start from highest / lowest)
    Make your own TESTS !!
    Be careful from CORNER CASES !
*/

Compilation message (stderr)

simurgh.cpp: In function 'void dfs(int, int)':
simurgh.cpp:43:45: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   43 |         if(mask != (1 << n) - 1 || v.size() < n -  1) return ;
      |                                    ~~~~~~~~~^~~~~~~~
simurgh.cpp:66:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |         for(int k = 0 ; k < a.size() ; k++) v.pop_back();
      |                         ~~^~~~~~~~~~

• Subtask 1: 0 / 13
• Subtask 2: 0 / 17
• Subtask 3: 0 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30