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답안 #759450

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
759450 2023-06-16T10:10:36 Z Hanksburger The Xana coup (BOI21_xanadu) C++17
100 / 100
 65 ms 18460 KB 
#include <bits/stdc++.h>
#define big (int)1e9
using namespace std;
int dp[100005][2][2], a[100005];
vector<int> adj[100005];
void dfs(int u, int p)
{
    for (int v:adj[u])
        if (v!=p)
            dfs(v, u);
    if (adj[u].size()==1 && p)
    {
        if (a[u])
        {
            dp[u][1][0]=big;
            dp[u][0][1]=big;
            dp[u][0][0]=0;
            dp[u][1][1]=1;
        }
        else
        {
            dp[u][1][0]=0;
            dp[u][0][1]=1;
            dp[u][0][0]=big;
            dp[u][1][1]=big;
        }
//        cout << "u=" << u << ": " << dp[u][1][0] << ' ' << dp[u][0][1] << ' ' << dp[u][0][0] << ' ' << dp[u][1][1] << '\n';
        return;
    }
    int x1, x2, x3, x4, start=0;
    for (int v:adj[u])
    {
        if (v==p)
            continue;
        if (start)
        {
            int y1=min(x1+dp[v][1][0], x3+dp[v][1][1]);
            int y2=min(x2+dp[v][0][0], x4+dp[v][0][1]);
            int y3=min(x3+dp[v][1][0], x1+dp[v][1][1]);
            int y4=min(x4+dp[v][0][0], x2+dp[v][0][1]);
            x1=min(y1, big);
            x2=min(y2, big);
            x3=min(y3, big);
            x4=min(y4, big);
        }
        else
        {
            x1=dp[v][1][a[u]];
            x2=dp[v][0][a[u]];
            x3=dp[v][1][!a[u]];
            x4=dp[v][0][!a[u]];
            start=1;
        }
    }
    dp[u][1][0]=x1;
    dp[u][0][1]=x2+1;
    dp[u][0][0]=x3;
    dp[u][1][1]=x4+1;
//    cout << "u=" << u << ": " << dp[u][1][0] << ' ' << dp[u][0][1] << ' ' << dp[u][0][0] << ' ' << dp[u][1][1] << '\n';
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    for (int i=1; i<n; i++)
    {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i=1; i<=n; i++)
        cin >> a[i];
    dfs(1, 0);
    if (min(dp[1][1][0], dp[1][1][1])>big/2)
        cout << "impossible";
    else
        cout << min(dp[1][1][0], dp[1][1][1]);
}

Compilation message

xanadu.cpp: In function 'void dfs(int, int)':
xanadu.cpp:58:19: warning: 'x4' may be used uninitialized in this function [-Wmaybe-uninitialized]
   58 |     dp[u][1][1]=x4+1;
      |                 ~~^~
xanadu.cpp:57:16: warning: 'x3' may be used uninitialized in this function [-Wmaybe-uninitialized]
   57 |     dp[u][0][0]=x3;
      |     ~~~~~~~~~~~^~~
xanadu.cpp:56:19: warning: 'x2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   56 |     dp[u][0][1]=x2+1;
      |                 ~~^~
xanadu.cpp:55:16: warning: 'x1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   55 |     dp[u][1][0]=x1;
      |     ~~~~~~~~~~~^~~

Subtask #1
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2564 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2564 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 1 ms 2676 KB Output is correct
7 Correct 3 ms 2676 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 1 ms 2684 KB Output is correct
14 Correct 1 ms 2680 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 1 ms 2644 KB Output is correct

Subtask #3
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 33 ms 18308 KB Output is correct
2 Correct 33 ms 18188 KB Output is correct
3 Correct 36 ms 18424 KB Output is correct

Subtask #4
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 35 ms 18372 KB Output is correct
2 Correct 52 ms 18196 KB Output is correct
3 Correct 53 ms 18460 KB Output is correct
4 Correct 30 ms 8308 KB Output is correct
5 Correct 32 ms 8956 KB Output is correct
6 Correct 32 ms 8968 KB Output is correct
7 Correct 2 ms 2644 KB Output is correct
8 Correct 12 ms 4820 KB Output is correct
9 Correct 32 ms 9028 KB Output is correct
10 Correct 45 ms 9200 KB Output is correct
11 Correct 65 ms 9712 KB Output is correct
12 Correct 36 ms 9872 KB Output is correct
13 Correct 30 ms 8624 KB Output is correct
14 Correct 32 ms 8964 KB Output is correct

Subtask #5
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2564 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 1 ms 2676 KB Output is correct
7 Correct 3 ms 2676 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 1 ms 2684 KB Output is correct
14 Correct 1 ms 2680 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 1 ms 2644 KB Output is correct
17 Correct 33 ms 18308 KB Output is correct
18 Correct 33 ms 18188 KB Output is correct
19 Correct 36 ms 18424 KB Output is correct
20 Correct 35 ms 18372 KB Output is correct
21 Correct 52 ms 18196 KB Output is correct
22 Correct 53 ms 18460 KB Output is correct
23 Correct 30 ms 8308 KB Output is correct
24 Correct 32 ms 8956 KB Output is correct
25 Correct 32 ms 8968 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Correct 12 ms 4820 KB Output is correct
28 Correct 32 ms 9028 KB Output is correct
29 Correct 45 ms 9200 KB Output is correct
30 Correct 65 ms 9712 KB Output is correct
31 Correct 36 ms 9872 KB Output is correct
32 Correct 30 ms 8624 KB Output is correct
33 Correct 32 ms 8964 KB Output is correct
34 Correct 1 ms 2680 KB Output is correct
35 Correct 1 ms 2644 KB Output is correct
36 Correct 1 ms 2644 KB Output is correct
37 Correct 1 ms 2644 KB Output is correct
38 Correct 2 ms 2644 KB Output is correct
39 Correct 1 ms 2644 KB Output is correct
40 Correct 1 ms 2644 KB Output is correct
41 Correct 1 ms 2644 KB Output is correct
42 Correct 1 ms 2644 KB Output is correct
43 Correct 1 ms 2676 KB Output is correct
44 Correct 2 ms 2680 KB Output is correct
45 Correct 35 ms 18320 KB Output is correct
46 Correct 42 ms 18100 KB Output is correct
47 Correct 33 ms 18388 KB Output is correct
48 Correct 29 ms 8288 KB Output is correct
49 Correct 33 ms 8872 KB Output is correct
50 Correct 43 ms 9080 KB Output is correct
51 Correct 2 ms 2644 KB Output is correct
52 Correct 12 ms 4776 KB Output is correct
53 Correct 35 ms 9168 KB Output is correct
54 Correct 34 ms 9144 KB Output is correct
55 Correct 34 ms 9624 KB Output is correct
56 Correct 32 ms 9924 KB Output is correct
57 Correct 47 ms 8632 KB Output is correct
58 Correct 35 ms 9036 KB Output is correct
59 Correct 15 ms 4768 KB Output is correct
60 Correct 30 ms 8448 KB Output is correct
61 Correct 43 ms 9036 KB Output is correct
62 Correct 32 ms 9136 KB Output is correct
63 Correct 38 ms 9172 KB Output is correct
64 Correct 32 ms 9216 KB Output is correct
65 Correct 30 ms 9556 KB Output is correct
66 Correct 28 ms 9548 KB Output is correct
67 Correct 27 ms 9452 KB Output is correct
68 Correct 36 ms 9412 KB Output is correct
69 Correct 32 ms 9412 KB Output is correct
70 Correct 25 ms 9380 KB Output is correct