Submission #767526

#	Time	Username	Problem	Language	Result	Execution time	Memory
767526		bLIC	Museum (CEOI17_museum)	C++17	45 / 100	3094 ms	246644 KiB

museum

/**
 *  Author: Anil Byar
**/

#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>

// using namespace __gnu_pbds;
using namespace std;

// template<class T>
// using ordered_set = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;



#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)(x).size()
#define uniq(v) v.erase(unique(all(v)), v.end())
#define ft first
#define sd second
#define pb push_back
#define eb emplace_back

// Source: https://codeforces.com/blog/entry/68809
// { start
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
// } end


typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vii;
typedef vector<ll> vl;
typedef vector<pll> vll;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
typedef vector<vl> vvl;

#define dbg if(0)

const ll MOD = 1e9+7;
const ll MOD9 = 998244353;
const ll INFLL = 1e18+5;
const int INF = 1e9;

void printbit(int x, int len) {string s="\n";while(len--){s=((x%2)?'1':'0')+s;x/=2;} cout<<s;}
ll power(ll x, ll y, ll mod){if (y==0) return 1;ll ret = power(x, y/2, mod);ret *= ret;ret%=mod;if (y&1) ret *= x;return ret%mod;}
ll modinv(ll x, ll mod = MOD) {return power(x, mod-2, mod);}

template<class T>
istream& operator>>(istream&in, vector<T>&v){
	for (T& x:v) in>>x;
	return in;
}
template<class T>
ostream& operator<<(ostream&out, vector<T>&v){
	for (T& x:v) out<<x<<' ';
	cout<<'\n';
	return out;
}
// use ?: with brackets (?:)
// check for overflow
// think about dp
// Read the statement carefully

const int N = 10001;

vii adj[N];
int n, k, x;
vi dp[N][2];

vi combine(vi& a, vi& b){
	vi tmp(sz(a)+sz(b)-1, INF);
	for (int i = 0;i<sz(a);i++) for (int j = 0;j<sz(b);j++){
		tmp[i+j] = min(tmp[i+j], a[i]+b[j]);
	}
	return tmp;
}

void dfs(int node, int par){
	dp[node][0] = dp[node][1] = {0};
	int p = sz(adj[node]);
	int q = sz(dp[node][1]);
	vvi pref(p);

	for (int i = 0;i<sz(adj[node]);i++){
		auto z = adj[node][i];
		adj[z.ft].erase(find(all(adj[z.ft]), make_pair(node, z.sd)));
		dfs(z.ft, node);
		assert(sz(dp[z.ft][0])==sz(dp[z.ft][1]));
		for (int j = 1;j<sz(dp[z.ft][1]);j++) {
			dp[z.ft][1][j] += 2*z.sd;
			dp[z.ft][0][j] += z.sd;
		}
		
		dp[node][1] = combine(dp[node][1], dp[z.ft][1]);
		pref[i] = dp[node][1];
	}
	vi suff = {0};
	vi tmp, v;
	for (int i = p-1;i>0;i--){
		int y = adj[node][i].ft;
		v = combine(pref[i-1], suff);
		tmp = combine(v, dp[y][0]);
		if (sz(dp[node][0])<sz(tmp)) dp[node][0].resize(sz(tmp), INF);
		for (int j = 0;j<sz(tmp);j++){
			dp[node][0][j] = min(dp[node][0][j], tmp[j]);
		}
		suff = combine(suff, dp[y][1]);
	}
	if (p){
		int y= adj[node][0].ft;
		tmp = combine(suff, dp[y][0]);
		if (sz(dp[node][0])<sz(tmp)) dp[node][0].resize(sz(tmp), INF);
		for (int j = 0;j<sz(tmp);j++){
			dp[node][0][j] = min(dp[node][0][j], tmp[j]);
		}
	}
	dp[node][0].pb(0);
	dp[node][1].pb(0);
	for (int i = sz(dp[node][0])-1;i>0;i--) {
		swap(dp[node][0][i], dp[node][0][i-1]);
		swap(dp[node][1][i], dp[node][1][i-1]);
	}
}

void solve(){
	cin>>n>>k>>x;
	for (int i = 0;i<n-1;i++){
		int u, v, w;cin>>u>>v>>w;
		adj[u].eb(v, w);
		adj[v].eb(u, w);
	}

	dfs(x, -1);
	cout<<dp[x][0][k];
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);


#define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
	freopen("input.in", "r", stdin);
	freopen("output.out", "w", stdout);
	freopen("debug.dbg", "w", stderr);
	int tt = clock();
#endif

	int t=1, i = 1;
	// cin>>t;
	while(t--){
		// cout<<"Case #"<<i++<<": ";
		solve();
		cout<<'\n';
	}
#ifndef ONLINE_JUDGE
	cerr << "TIME = " << (float)(clock() - tt)/CLOCKS_PER_SEC << endl;
	tt = clock();
#endif
}

Compilation message (stderr)

museum.cpp: In function 'void dfs(int, int)':
museum.cpp:112:6: warning: unused variable 'q' [-Wunused-variable]
  112 |  int q = sz(dp[node][1]);
      |      ^
museum.cpp: In function 'int main()':
museum.cpp:182:11: warning: unused variable 'i' [-Wunused-variable]
  182 |  int t=1, i = 1;
      |           ^

• Subtask 1: 20 / 20
• Subtask 2: 25 / 25
• Subtask 3: 0 / 35
• Subtask 4: 0 / 20