Submission #282591

#	Time	Username	Problem	Language	Result	Execution time	Memory
282591		AMO5	Političari (COCI20_politicari)	C++17	70 / 70	20 ms	2560 KiB

politicari

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define eb emplace_back
#define mt make_tuple
#define all(x) (x).begin(), (x).end()  
#define sz(x) int(x.size()) 
#define MOD 1000000007

typedef long long ll;
typedef pair <int, int> ii;
typedef pair <ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef long double ld;

const ll INF=63;
const int mxn=505;
bool DEBUG=0;

int n,a[mxn][mxn],vis[mxn][mxn];
ll k;

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    //freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
    cin>>n>>k;
    for(int i=1; i<=n; i++){
		for(int j=1; j<=n; j++){
			cin>>a[i][j];
		}
	}
	if(k==1){
		cout<<1<<"\n";
		return 0;
	}
	if(k==2){
		cout<<2<<"\n";
		return 0;
	}
	int ptr=3,now=2,prev=1;
	vi list;
	while(!vis[now][prev]){
		//cerr<<ptr<<" "<<now<<" "<<prev<<"\n";
		vis[now][prev]=ptr;
		int pr = now;
		now=a[now][prev];
		prev = pr;
		if(ptr==k){
			cout<<now<<"\n";
			return 0;
		}
		ptr++;
		list.eb(now);
	}
	
	k-=vis[now][prev];
	ll siz = 1LL*(ptr-vis[now][prev]);
	k=k%siz;
	cout<<list[k+vis[now][prev]-1-2];
	return 0;
}
	
// READ & UNDERSTAND
// ll, int overflow, array bounds, memset(0)
// special cases (n=1?), n+1 (1-index)
// do smth instead of nothing & stay organized
// WRITE STUFF DOWN

• Subtask 1: 70 / 70