Submission #538074

#	Time	Username	Problem	Language	Result	Execution time	Memory
538074		kym	Speedrun (RMI21_speedrun)	C++14	0 / 100	100 ms	1556 KiB

speedrun

/* Input format:
 *
 * N -- number of nodes
 * a1 b1 -- edge 1
 * ...
 * a(N-1) b(N-1) -- edge N - 1
 * x -- start node
 */
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,s,e) for(ll i = s; i <= (ll)e; ++i)
#define DEC(i,s,e) for(ll i = s; i >= (ll)e; --i)
#define IAMSPEED ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
#define db(x) cerr << #x << "=" << x << "\n"
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << "\n"
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<"\n"
#define dbv(v) cerr << #v << ":"; for (auto ite : v) cerr << ite << ' '; cerr <<"\n"
#define dbvp(v) cerr << #v << ":"; for (auto ite : v) cerr << "{"  << ite.f << ',' << ite.s << "} "; cerr << "\n"
#define dba(a,ss,ee) cerr << #a << ":"; FOR(ite,ss,ee) cerr << a[ite] << ' '; cerr << "\n"
#define reach cerr << "LINE: " << __LINE__ << "\n";
#else
#define db(x)
#define db2(x,y)
#define db3(a,b,c)
#define dbv(v)
#define dbvp(v)
#define dba(a,ss,ee)
#define reach 
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define ll long long 
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define f first
#define s second
#define g0(x) get<0>(x)
#define g1(x) get<1>(x)
#define g2(x) get<2>(x)
#define g3(x) get<3>(x)
typedef pair <ll, ll> pi;
typedef tuple<ll,ll,ll> ti3;
typedef tuple<ll,ll,ll,ll> ti4;
ll rand(ll a, ll b) { return a + rng() % (b-a+1); }
const int MOD = 1e9 + 7;
const int inf = (int)1e9 + 500;
const long long oo = (ll)1e18 + 500;
template <typename T> void chmax(T& a, const T b) { a=max(a,b); }
template <typename T> void chmin(T& a, const T b) { a=min(a,b); }
const int MAXN = -1;
 
#include "speedrun.h"
#ifdef LOCAL
void setHintLen(int l);
void setHint(int i, int j, bool b);
int getLength() ;
bool getHint(int j);
bool goTo(int x);
#endif
vector<int> V[1005];
set<int> lft[1005];
int par[1005]; 
int match[1005];
void dfs(int x, int p ) {
	par[x] = p;
	for(auto v:V[x]) {
		if(v==p)continue;
		dfs(v,x);
	}
}
 
void gethints(int x, int p) {
	FOR(bit,0,9)if((1<<bit)&p)setHint(x,bit+1,1);
	if(p != 0)lft[x].erase(p);
	if(lft[x].size()) {
		//dbv(lft[x]);
		vector<int> children;
		for(auto i:lft[x])children.pb(i); // now the children will get each other
		FOR(i,0,children.size()-1) { // the last child contain the leaf that carries that information for the parent
			if(i != (int)children.size()-1 )match[children[i]] = children[i+1];	
			gethints(children[i],x);	
		}
		FOR(bit,0,9)if((1<<bit)&children[0])setHint(x,10+bit+1,1);
	} else {
		int cx = x;
		while(match[x] == -1 && x != 0) {
			x=par[x];
		}
		if(match[x] != -1) {
			FOR(bit,0,9)if((1<<bit)&match[x])setHint(cx,10+bit+1,1);
		}
	} 
	
}
 
void assignHints(int subtask, int n, int A[], int B[]) { /* your solution here */
	memset(match,-1,sizeof match);
	FOR(i,1,n-1) {
		V[A[i]].pb(B[i]);
		V[B[i]].pb(A[i]);
		lft[A[i]].insert(B[i]);
		lft[B[i]].insert(A[i]);
	}
	dfs(1,0);
	setHintLen(20);
	gethints(1,0);
}
int build1() {
	int r = 0;
	FOR(i,0,9){
		bool st = getHint(i+1);
		if(st) r += 1<<i;
	}
	return r;
}
int build2() {
	int r = 0;
	FOR(i,0,9){
		bool st = getHint(i+11);
		if(st) r += 1<<i;
	}
	return r;
}
void speedrun(int subtask, int N, int start) { /* your solution here */
	int x = start;
 
	while(x != 1) {
		int x=build1();
		assert(x>=1);
		assert(x<=N);
		goTo(x);
		if(x==1)break;
	}
	// im at the root now
	set<int> s;
	s.insert(1);
	reach
	for(;(int)s.size() < N;) {
		db(x);
		int b2 = build2();
		assert(b2 >= 1);
		assert(b2 <= N);
		bool r = goTo(b2);
		if(r) {
			x=b2;
			s.insert(x);
			continue;		
		} else {//root
			assert(par[x] >= 1); 
			assert(par[x] <= N);
			goTo(par[x]);
			x=par[x];
			while(goTo(b2) == 0) {
				assert(par[x] >= 1); 
				assert(par[x] <= N);
				goTo(par[x]);
				x = par[x];
			}  
			x=b2;
			s.insert(x);
			
		}
	}
	
}
#ifdef LOCAL
using namespace std;
 
static map<int, map<int, bool>> mp;
static int length = -1;
static int queries = 0;
static bool length_set = false;
static int current_node = 0;
static set<int> viz;
static map<int, set<int>> neighbours;
 
void setHintLen(int l) {
    if (length_set) {
        cerr << "Cannot call setHintLen twice" << endl;
        exit(0);
    }
    length = l;
    length_set = true;
}
 
void setHint(int i, int j, bool b) {
    if (!length_set) {
        cerr << "Must call setHintLen before setHint" << endl;
        exit(0);
    }
    mp[i][j] = b;
}
 
int getLength() { return length; }
 
bool getHint(int j) { return mp[current_node][j]; }
 
bool goTo(int x) {
	db2("GOTO: ", x);
    if (neighbours[current_node].find(x) == end(neighbours[current_node])) {
        ++queries;
        return false;
    } else {
        viz.insert(current_node = x);
        return true;
    }
}
 
int main() {
    int N;
    cin >> N;
 
    int a[N], b[N];
    for (int i = 1; i < N; ++i) {
        cin >> a[i] >> b[i];
        neighbours[a[i]].insert(b[i]);
        neighbours[b[i]].insert(a[i]);
    }
 
    assignHints(1, N, a, b);
	reach
    if (!length_set) {
        cerr << "Must call setHintLen at least once" << endl;
        exit(0);
    }
 
    cin >> current_node;
    viz.insert(current_node);
 
    speedrun(1, N, current_node);
 
    if ((int)viz.size() < N) {
        cerr << "Haven't seen all nodes" << endl;
        exit(0);
    }
 
    cerr << "OK; " << queries << " incorrect goto's" << endl;
    return 0;
}
#endif

• Subtask 1: 0 / 21
• Subtask 2: 0 / 8
• Subtask 3: 0 / 19
• Subtask 4: 0 / 12
• Subtask 5: 0 / 40