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답안 #533676

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
533676 2022-03-06T22:09:28 Z kevinyang The Xana coup (BOI21_xanadu) C++17
100 / 100
 75 ms 28248 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long
int n;
const int mxn = 100005;
vector<int> adj[mxn];
int a[mxn];
int dp[2][2][mxn];//dp[used or not][node i is lit up or not][node i] = min cost to reach said state
void dfs(int u, int p){
    int c = 0;
    for(int nxt: adj[u]){
        if(nxt==p)continue;
        dfs(nxt,u);
        c++;
    }
    if(c==0){  
        if(a[u]==0){
            dp[0][0][u] = 0;
            dp[1][1][u] = 1;
            dp[0][1][u] = dp[1][0][u] = (int)1e9;
        }
        else{
            dp[0][0][u] = dp[1][1][u] = (int)1e9;
            dp[0][1][u] = 0;
            dp[1][0][u] = 1;
        }
    }
    else{
        vector<int>nodes;
        for(int nxt: adj[u]){
            if(nxt==p)continue;
            nodes.push_back(nxt);
        }
        dp[0][0][u] = dp[0][1][u] = dp[1][0][u] = dp[1][1][u] = (int)1e9;
        if(true){
            int sum = 0;
            vector<int>arr;
            for(int i = 0; i<c; i++){
                int x = dp[0][0][nodes[i]];
                int y = dp[1][0][nodes[i]];
                arr.push_back(y-x);
                sum+=x;
            }
            int cur = a[u]^1;
            sort(arr.begin(),arr.end());
            dp[1][cur][u] = min(dp[1][cur][u],sum+1);
            for(int i = 0; i<c; i++){
                cur^=1;
                sum+=arr[i];
                dp[1][cur][u] = min(dp[1][cur][u],sum+1);
            }
        }
        if(true){
            int sum = 0;
            vector<int>arr;
            for(int i = 0; i<c; i++){
                int x = dp[0][1][nodes[i]];
                int y = dp[1][1][nodes[i]];
                arr.push_back(y-x);
                sum+=x;
            }
            int cur = a[u];
            sort(arr.begin(),arr.end());
            dp[0][cur][u] = min(dp[0][cur][u],sum);
            for(int i = 0; i<c; i++){
                cur^=1;
                sum+=arr[i];
                dp[0][cur][u] = min(dp[0][cur][u],sum);
            }
        }
        /*
        for(int i = 0; i<(1LL<<c); i++){
            for(int j = 0; j<(1LL<<c); j++){
                int used = a[u];
                for(int a = 0; a<c; a++){
                    if(i&(1LL<<a)){
                        used^=1;
                    }
                }
                int sum = 0;
                int tot = 0;
                for(int a = 0; a<c; a++){
                    int x = (i&(1LL<<a));
                    int y = (j&(1LL<<a));
                    if(x>0)x = 1;
                    if(y>0)y = 1;
                    tot+=dp[x][y][nodes[a]];
                }
                for(int a = 0; a<c; a++){
                    if(j&(1LL<<a)){
                        sum++;
                    }
                }
                if(sum!=0&&sum!=c)continue;
                if(sum==0){
                    dp[1][used^1][u] = min(dp[1][used^1][u],tot+1);
                }
                else{
                    dp[0][used][u] = min(dp[0][used][u],tot);
                }
            }
        }
        */
    }
}
signed main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n;
    for(int i = 1; i<n; i++){
        int x,y;
        cin >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    for(int i = 1; i<=n; i++){
        cin >> a[i];
        a[i]^=1;
    }
    dfs(1,0);
    /*
    for(int i = 1; i<=n; i++){
        for(int a = 0; a<2; a++){
            for(int b = 0; b<2; b++){
                cout << dp[a][b][i] << " ";
            }
        }
        cout << "\n";
    }
    */
    int v = min(dp[0][1][1],dp[1][1][1]);
    if(v>(int)1e6)cout << "impossible\n";
    else cout << v << "\n";
    return 0;
}

Subtask #1
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2672 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2676 KB Output is correct
4 Correct 2 ms 2616 KB Output is correct
5 Correct 2 ms 2672 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2672 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2676 KB Output is correct
4 Correct 2 ms 2616 KB Output is correct
5 Correct 2 ms 2672 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 2 ms 2676 KB Output is correct
9 Correct 2 ms 2636 KB Output is correct
10 Correct 2 ms 2636 KB Output is correct
11 Correct 2 ms 2636 KB Output is correct
12 Correct 2 ms 2636 KB Output is correct
13 Correct 2 ms 2636 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2672 KB Output is correct
16 Correct 2 ms 2672 KB Output is correct

Subtask #3
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 63 ms 28020 KB Output is correct
2 Correct 58 ms 27728 KB Output is correct
3 Correct 75 ms 28248 KB Output is correct

Subtask #4
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 59 ms 28108 KB Output is correct
2 Correct 65 ms 27788 KB Output is correct
3 Correct 62 ms 28188 KB Output is correct
4 Correct 63 ms 10848 KB Output is correct
5 Correct 63 ms 11716 KB Output is correct
6 Correct 66 ms 11832 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 18 ms 5756 KB Output is correct
9 Correct 63 ms 11496 KB Output is correct
10 Correct 69 ms 11748 KB Output is correct
11 Correct 74 ms 12764 KB Output is correct
12 Correct 68 ms 12996 KB Output is correct
13 Correct 61 ms 11560 KB Output is correct
14 Correct 63 ms 12160 KB Output is correct

Subtask #5
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2672 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2676 KB Output is correct
4 Correct 2 ms 2616 KB Output is correct
5 Correct 2 ms 2672 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 2 ms 2676 KB Output is correct
9 Correct 2 ms 2636 KB Output is correct
10 Correct 2 ms 2636 KB Output is correct
11 Correct 2 ms 2636 KB Output is correct
12 Correct 2 ms 2636 KB Output is correct
13 Correct 2 ms 2636 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2672 KB Output is correct
16 Correct 2 ms 2672 KB Output is correct
17 Correct 63 ms 28020 KB Output is correct
18 Correct 58 ms 27728 KB Output is correct
19 Correct 75 ms 28248 KB Output is correct
20 Correct 59 ms 28108 KB Output is correct
21 Correct 65 ms 27788 KB Output is correct
22 Correct 62 ms 28188 KB Output is correct
23 Correct 63 ms 10848 KB Output is correct
24 Correct 63 ms 11716 KB Output is correct
25 Correct 66 ms 11832 KB Output is correct
26 Correct 2 ms 2636 KB Output is correct
27 Correct 18 ms 5756 KB Output is correct
28 Correct 63 ms 11496 KB Output is correct
29 Correct 69 ms 11748 KB Output is correct
30 Correct 74 ms 12764 KB Output is correct
31 Correct 68 ms 12996 KB Output is correct
32 Correct 61 ms 11560 KB Output is correct
33 Correct 63 ms 12160 KB Output is correct
34 Correct 2 ms 2636 KB Output is correct
35 Correct 2 ms 2672 KB Output is correct
36 Correct 2 ms 2672 KB Output is correct
37 Correct 2 ms 2636 KB Output is correct
38 Correct 2 ms 2636 KB Output is correct
39 Correct 2 ms 2672 KB Output is correct
40 Correct 2 ms 2636 KB Output is correct
41 Correct 2 ms 2636 KB Output is correct
42 Correct 2 ms 2636 KB Output is correct
43 Correct 2 ms 2636 KB Output is correct
44 Correct 2 ms 2636 KB Output is correct
45 Correct 65 ms 28080 KB Output is correct
46 Correct 58 ms 27716 KB Output is correct
47 Correct 64 ms 28180 KB Output is correct
48 Correct 59 ms 10992 KB Output is correct
49 Correct 60 ms 11676 KB Output is correct
50 Correct 65 ms 11824 KB Output is correct
51 Correct 2 ms 2636 KB Output is correct
52 Correct 19 ms 5652 KB Output is correct
53 Correct 65 ms 11588 KB Output is correct
54 Correct 73 ms 11756 KB Output is correct
55 Correct 65 ms 12744 KB Output is correct
56 Correct 69 ms 13124 KB Output is correct
57 Correct 58 ms 11560 KB Output is correct
58 Correct 64 ms 12172 KB Output is correct
59 Correct 18 ms 5548 KB Output is correct
60 Correct 54 ms 10660 KB Output is correct
61 Correct 61 ms 11428 KB Output is correct
62 Correct 63 ms 11680 KB Output is correct
63 Correct 73 ms 11752 KB Output is correct
64 Correct 75 ms 11720 KB Output is correct
65 Correct 46 ms 11980 KB Output is correct
66 Correct 47 ms 12024 KB Output is correct
67 Correct 42 ms 14428 KB Output is correct
68 Correct 40 ms 14432 KB Output is correct
69 Correct 41 ms 14360 KB Output is correct
70 Correct 41 ms 14356 KB Output is correct