oj.uz

답안 #415201

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
415201 2021-05-31T16:37:31 Z amunduzbaev The Xana coup (BOI21_xanadu) C++14
100 / 100
 145 ms 30824 KB 
/* made by amunduzbaev */

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

using namespace std;
//~ using namespace __gnu_pbds;

#define ff first
#define ss second
#define vv vector
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define mem(arr, v) memset(arr, v, sizeof arr)
#define NeedForSpeed ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define int long long

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef vector<int> vii;
typedef vector<pii> vpii;
template<class T> bool umin(T& a, const T& b) { return a > b ? a = b, true : false; }
template<class T> bool umax(T& a, const T& b) { return a < b ? a = b, true : false; }
template<int sz> using tut = array<int, sz>;
void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);
  freopen((s+".out").c_str(),"w",stdout); NeedForSpeed }
//~ template<class T> using oset = tree<T,
//~ null_type, less_equal<T>, rb_tree_tag,
//~ tree_order_statistics_node_update> ordered_set;

const int N = 2e5+5;
const int mod = 1e9+7;
const ll inf = 1e18;
const ld Pi = acos(-1);

#define MULTI 0
int n, m, k, s, t, q, ans, res, a[N];
int dp[N][2][2];
vii edges[N];

void dfs(int u, int p = -1){
	vii ch;
	for(auto x : edges[u]){
		if(x == p) continue;
		ch.pb(x), dfs(x, u);
	} 
	if(!sz(ch)) dp[u][a[u]][0] = 0, dp[u][a[u] ^ 1][1] = 1;
	else if(sz(ch) == 1){ int x = ch[0];
		umin(dp[u][a[u]][0], dp[x][0][0]);
		umin(dp[u][a[u]][1], dp[x][1][1] + 1);
		umin(dp[u][a[u]^1][0], dp[x][0][1]);
		umin(dp[u][a[u]^1][1], dp[x][1][0] + 1);
	} else if(sz(ch) == 2){
		int lx = ch[0], rx = ch[1];
		umin(dp[u][a[u]][0], min(dp[lx][0][0] + dp[rx][0][0], dp[lx][0][1] + dp[rx][0][1]));
		umin(dp[u][a[u]][1], min(dp[lx][1][0] + dp[rx][1][1], dp[lx][1][1] + dp[rx][1][0]) + 1);
		umin(dp[u][a[u]^1][0], min(dp[lx][0][1] + dp[rx][0][0], dp[lx][0][0] + dp[rx][0][1]));
		umin(dp[u][a[u]^1][1], min(dp[lx][1][1] + dp[rx][1][1], dp[lx][1][0] + dp[rx][1][0]) + 1);
	} else {
		vpii tt;
		int sum = 0;
		// vertex u, color a[u], not using itself
		for(auto x : ch) sum += dp[x][0][0], tt.pb({dp[x][0][1] - dp[x][0][0], x});
		sort(all(tt));
		umin(dp[u][a[u]][0], sum);
		for(int i=1;i<sz(ch);i+=2) sum += tt[i].ff + tt[i-1].ff, umin(dp[u][a[u]][0], sum);
		
		// vertex u, color a[u], using itself
		tt.clear(); sum = 0; 
		for(auto x : ch) sum += dp[x][1][0], tt.pb({dp[x][1][1] - dp[x][1][0], x});
		sort(all(tt));
		sum += tt[0].ff;
		umin(dp[u][a[u]][1], sum + 1);
		for(int i=2;i<sz(tt);i+=2) sum += tt[i].ff, sum += tt[i-1].ff, umin(dp[u][a[u]][1], sum + 1);
		
		//vertex u, color a[u]^1, not using itself
		tt.clear(); sum = 0; 
		for(auto x : ch) sum += dp[x][0][0], tt.pb({dp[x][0][1] - dp[x][0][0], x});
		sort(all(tt));
		sum += tt[0].ff;
		umin(dp[u][a[u]^1][0], sum);
		for(int i=2;i<sz(tt);i+=2) sum += tt[i].ff, sum += tt[i-1].ff, umin(dp[u][a[u]^1][0], sum);
		
		// vertex u, color a[u]^1, using itself
		tt.clear(); sum = 0; 
		for(auto x : ch) sum += dp[x][1][0], tt.pb({dp[x][1][1] - dp[x][1][0], x});
		sort(all(tt));
		umin(dp[u][a[u]^1][1], sum + 1);
		for(int i=1;i<sz(tt);i+=2) sum += tt[i].ff, sum += tt[i-1].ff, umin(dp[u][a[u]^1][1], sum + 1);
	}
}

/*

5
1 2 
2 3
3 4
4 5
0 1 1 1 1

*/

void solve(int t_case){
	cin>>n;
	for(int i=1;i<n;i++){
		int a, b; cin>>a>>b;
		edges[a].pb(b), edges[b].pb(a);
	} for(int i=1;i<=n;i++) cin>>a[i];
	int root = 1;
	for(int i=1;i<=n;i++) dp[i][0][0] = dp[i][0][1] = dp[i][1][0] = dp[i][1][1] = mod;
	for(int i=1;i<=n;i++) if(sz(edges[i]) <= 2ll) { root = i; break; }
	dfs(root);
	
	int res = min(dp[root][0][0], dp[root][0][1]);
	if(res == mod) cout<<"impossible\n"; 
	else cout<<res<<"\n";
}

signed main(){
	NeedForSpeed
	if(MULTI){
		int t; cin>>t;
		for(int t_case = 1; t_case <= t; t_case++) solve(t_case);
	} else solve(1);
	return 0;
}

Compilation message

xanadu.cpp: In function 'void usaco(std::string)':
xanadu.cpp:33:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 | void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xanadu.cpp:34:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |   freopen((s+".out").c_str(),"w",stdout); NeedForSpeed }
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 4940 KB Output is correct
2 Correct 24 ms 4940 KB Output is correct
3 Correct 4 ms 4940 KB Output is correct
4 Correct 4 ms 4960 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 4940 KB Output is correct
2 Correct 24 ms 4940 KB Output is correct
3 Correct 4 ms 4940 KB Output is correct
4 Correct 4 ms 4960 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 4 ms 4940 KB Output is correct
7 Correct 4 ms 4940 KB Output is correct
8 Correct 4 ms 4940 KB Output is correct
9 Correct 4 ms 4940 KB Output is correct
10 Correct 4 ms 4940 KB Output is correct
11 Correct 5 ms 4940 KB Output is correct
12 Correct 4 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 4 ms 4940 KB Output is correct
15 Correct 4 ms 4940 KB Output is correct
16 Correct 4 ms 4940 KB Output is correct

Subtask #3
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 101 ms 30788 KB Output is correct
2 Correct 76 ms 30360 KB Output is correct
3 Correct 107 ms 30788 KB Output is correct

Subtask #4
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 83 ms 30660 KB Output is correct
2 Correct 106 ms 30356 KB Output is correct
3 Correct 86 ms 30716 KB Output is correct
4 Correct 80 ms 12084 KB Output is correct
5 Correct 72 ms 12696 KB Output is correct
6 Correct 88 ms 12904 KB Output is correct
7 Correct 4 ms 5068 KB Output is correct
8 Correct 67 ms 7584 KB Output is correct
9 Correct 74 ms 12572 KB Output is correct
10 Correct 84 ms 12740 KB Output is correct
11 Correct 145 ms 13872 KB Output is correct
12 Correct 79 ms 14060 KB Output is correct
13 Correct 109 ms 12700 KB Output is correct
14 Correct 115 ms 13172 KB Output is correct

Subtask #5
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 4940 KB Output is correct
2 Correct 24 ms 4940 KB Output is correct
3 Correct 4 ms 4940 KB Output is correct
4 Correct 4 ms 4960 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 4 ms 4940 KB Output is correct
7 Correct 4 ms 4940 KB Output is correct
8 Correct 4 ms 4940 KB Output is correct
9 Correct 4 ms 4940 KB Output is correct
10 Correct 4 ms 4940 KB Output is correct
11 Correct 5 ms 4940 KB Output is correct
12 Correct 4 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 4 ms 4940 KB Output is correct
15 Correct 4 ms 4940 KB Output is correct
16 Correct 4 ms 4940 KB Output is correct
17 Correct 101 ms 30788 KB Output is correct
18 Correct 76 ms 30360 KB Output is correct
19 Correct 107 ms 30788 KB Output is correct
20 Correct 83 ms 30660 KB Output is correct
21 Correct 106 ms 30356 KB Output is correct
22 Correct 86 ms 30716 KB Output is correct
23 Correct 80 ms 12084 KB Output is correct
24 Correct 72 ms 12696 KB Output is correct
25 Correct 88 ms 12904 KB Output is correct
26 Correct 4 ms 5068 KB Output is correct
27 Correct 67 ms 7584 KB Output is correct
28 Correct 74 ms 12572 KB Output is correct
29 Correct 84 ms 12740 KB Output is correct
30 Correct 145 ms 13872 KB Output is correct
31 Correct 79 ms 14060 KB Output is correct
32 Correct 109 ms 12700 KB Output is correct
33 Correct 115 ms 13172 KB Output is correct
34 Correct 5 ms 4940 KB Output is correct
35 Correct 5 ms 4940 KB Output is correct
36 Correct 5 ms 4940 KB Output is correct
37 Correct 4 ms 4940 KB Output is correct
38 Correct 4 ms 4940 KB Output is correct
39 Correct 4 ms 4940 KB Output is correct
40 Correct 4 ms 4940 KB Output is correct
41 Correct 4 ms 4940 KB Output is correct
42 Correct 3 ms 4940 KB Output is correct
43 Correct 4 ms 4940 KB Output is correct
44 Correct 4 ms 4940 KB Output is correct
45 Correct 78 ms 30656 KB Output is correct
46 Correct 82 ms 30384 KB Output is correct
47 Correct 109 ms 30824 KB Output is correct
48 Correct 94 ms 12084 KB Output is correct
49 Correct 112 ms 12792 KB Output is correct
50 Correct 116 ms 12884 KB Output is correct
51 Correct 4 ms 5068 KB Output is correct
52 Correct 30 ms 7560 KB Output is correct
53 Correct 108 ms 12584 KB Output is correct
54 Correct 132 ms 12688 KB Output is correct
55 Correct 94 ms 13716 KB Output is correct
56 Correct 86 ms 14128 KB Output is correct
57 Correct 79 ms 12716 KB Output is correct
58 Correct 89 ms 13196 KB Output is correct
59 Correct 30 ms 7468 KB Output is correct
60 Correct 107 ms 11840 KB Output is correct
61 Correct 113 ms 12608 KB Output is correct
62 Correct 88 ms 12584 KB Output is correct
63 Correct 103 ms 12608 KB Output is correct
64 Correct 83 ms 12640 KB Output is correct
65 Correct 95 ms 13084 KB Output is correct
66 Correct 99 ms 12996 KB Output is correct
67 Correct 121 ms 15800 KB Output is correct
68 Correct 101 ms 15828 KB Output is correct
69 Correct 117 ms 15808 KB Output is correct
70 Correct 105 ms 15752 KB Output is correct