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Submission #894474

# Submission time Handle Problem Language Result Execution time Memory
894474 2023-12-28T10:41:35 Z vjudge1 The Xana coup (BOI21_xanadu) C++17
100 / 100
 92 ms 15536 KB 
#include<bits/stdc++.h>
 
using namespace std;

#define int long long

const int N = 100000;
const int INF = 1e11;

vector<int> adj[N];
int dp[4][N]; //0 - I don't toggle. 1 - I toggle. 2, 3 - same but the camera is not off.
int initial[N];

void get0(int x, int p){
    if(initial[x] == 0){
        int ans = 0;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[0][node];
                change.push_back(dp[1][node] - dp[0][node]);
            }
        }
        sort(change.begin(), change.end());
        int mn = 0;
        int curr = 0;
        for(int i = 0; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[0][x] = ans + mn;
    }else{
        dp[0][x] = INF;
        int ans = 0;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[0][node];
                change.push_back(dp[1][node] - dp[0][node]);
            }
        }
        if(change.empty()) return;
        sort(change.begin(), change.end());
        int mn = change[0];
        int curr = change[0];
        for(int i = 1; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[0][x] = ans + mn;
    }
}

void get1(int x, int p){
    if(initial[x] == 1){
        int ans = 1;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[2][node];
                change.push_back(dp[3][node] - dp[2][node]);
            }
        }
        sort(change.begin(), change.end());
        int mn = 0;
        int curr = 0;
        for(int i = 0; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[1][x] = ans + mn;
    }else{
        dp[1][x] = INF;
        int ans = 1;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[2][node];
                change.push_back(dp[3][node] - dp[2][node]);
            }
        }
        if(change.empty()) return;
        sort(change.begin(), change.end());
        int mn = change[0];
        int curr = change[0];
        for(int i = 1; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[1][x] = ans + mn;
    }
}

void get2(int x, int p){
    if(initial[x] == 1){
        int ans = 0;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[0][node];
                change.push_back(dp[1][node] - dp[0][node]);
            }
        }
        sort(change.begin(), change.end());
        int mn = 0;
        int curr = 0;
        for(int i = 0; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[2][x] = ans + mn;
    }else{
        dp[2][x] = INF;
        int ans = 0;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[0][node];
                change.push_back(dp[1][node] - dp[0][node]);
            }
        }
        if(change.empty()) return;
        sort(change.begin(), change.end());
        int mn = change[0];
        int curr = change[0];
        for(int i = 1; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[2][x] = ans + mn;
    }
}

void get3(int x, int p){
    if(initial[x] == 0){
        int ans = 1;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[2][node];
                change.push_back(dp[3][node] - dp[2][node]);
            }
        }
        sort(change.begin(), change.end());
        int mn = 0;
        int curr = 0;
        for(int i = 0; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[3][x] = ans + mn;
    }else{
        dp[3][x] = INF;
        int ans = 1;
        vector<int> change;
        for(int node : adj[x]){
            if(node != p){
                ans += dp[2][node];
                change.push_back(dp[3][node] - dp[2][node]);
            }
        }
        if(change.empty()) return;
        sort(change.begin(), change.end());
        int mn = change[0];
        int curr = change[0];
        for(int i = 1; i + 1 < (int)change.size(); i += 2){
            curr += change[i] + change[i+1];
            mn = min(mn, curr);
        }
        dp[3][x] = ans + mn;
    }
}

void DFS(int x, int p){
    for(int node : adj[x]){
        if(node != p) DFS(node, x);
    }
    get0(x, p);
    get1(x, p);
    get2(x, p);
    get3(x, p);
}

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n; cin >> n;
    for(int i = 0; i < n - 1; i++){
        int a, b; cin >> a >> b; a--; b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    for(int i = 0; i < n; i++) cin >> initial[i];
    DFS(0, -1);
    if(min(dp[0][0], dp[1][0]) >= 1e6) cout << "impossible\n";
    else cout << min(dp[0][0], dp[1][0]) << "\n";
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 2 ms 6544 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6488 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 2 ms 6544 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6488 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct
6 Correct 2 ms 6488 KB Output is correct
7 Correct 2 ms 6488 KB Output is correct
8 Correct 2 ms 6492 KB Output is correct
9 Correct 2 ms 6488 KB Output is correct
10 Correct 1 ms 6536 KB Output is correct
11 Correct 2 ms 6492 KB Output is correct
12 Correct 2 ms 6492 KB Output is correct
13 Correct 2 ms 6544 KB Output is correct
14 Correct 1 ms 6492 KB Output is correct
15 Correct 1 ms 6492 KB Output is correct
16 Correct 1 ms 6492 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 42 ms 15444 KB Output is correct
2 Correct 56 ms 15440 KB Output is correct
3 Correct 51 ms 15452 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 42 ms 15472 KB Output is correct
2 Correct 53 ms 15408 KB Output is correct
3 Correct 52 ms 15456 KB Output is correct
4 Correct 52 ms 10836 KB Output is correct
5 Correct 78 ms 11660 KB Output is correct
6 Correct 84 ms 11736 KB Output is correct
7 Correct 2 ms 6488 KB Output is correct
8 Correct 28 ms 8316 KB Output is correct
9 Correct 69 ms 11348 KB Output is correct
10 Correct 84 ms 11264 KB Output is correct
11 Correct 67 ms 11612 KB Output is correct
12 Correct 78 ms 11752 KB Output is correct
13 Correct 62 ms 11348 KB Output is correct
14 Correct 84 ms 12036 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 2 ms 6544 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6488 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct
6 Correct 2 ms 6488 KB Output is correct
7 Correct 2 ms 6488 KB Output is correct
8 Correct 2 ms 6492 KB Output is correct
9 Correct 2 ms 6488 KB Output is correct
10 Correct 1 ms 6536 KB Output is correct
11 Correct 2 ms 6492 KB Output is correct
12 Correct 2 ms 6492 KB Output is correct
13 Correct 2 ms 6544 KB Output is correct
14 Correct 1 ms 6492 KB Output is correct
15 Correct 1 ms 6492 KB Output is correct
16 Correct 1 ms 6492 KB Output is correct
17 Correct 42 ms 15444 KB Output is correct
18 Correct 56 ms 15440 KB Output is correct
19 Correct 51 ms 15452 KB Output is correct
20 Correct 42 ms 15472 KB Output is correct
21 Correct 53 ms 15408 KB Output is correct
22 Correct 52 ms 15456 KB Output is correct
23 Correct 52 ms 10836 KB Output is correct
24 Correct 78 ms 11660 KB Output is correct
25 Correct 84 ms 11736 KB Output is correct
26 Correct 2 ms 6488 KB Output is correct
27 Correct 28 ms 8316 KB Output is correct
28 Correct 69 ms 11348 KB Output is correct
29 Correct 84 ms 11264 KB Output is correct
30 Correct 67 ms 11612 KB Output is correct
31 Correct 78 ms 11752 KB Output is correct
32 Correct 62 ms 11348 KB Output is correct
33 Correct 84 ms 12036 KB Output is correct
34 Correct 2 ms 6488 KB Output is correct
35 Correct 2 ms 6544 KB Output is correct
36 Correct 2 ms 6540 KB Output is correct
37 Correct 2 ms 6488 KB Output is correct
38 Correct 4 ms 6492 KB Output is correct
39 Correct 2 ms 6544 KB Output is correct
40 Correct 2 ms 6492 KB Output is correct
41 Correct 2 ms 6492 KB Output is correct
42 Correct 2 ms 6492 KB Output is correct
43 Correct 2 ms 6492 KB Output is correct
44 Correct 2 ms 6492 KB Output is correct
45 Correct 60 ms 15348 KB Output is correct
46 Correct 65 ms 15408 KB Output is correct
47 Correct 55 ms 15536 KB Output is correct
48 Correct 80 ms 11168 KB Output is correct
49 Correct 92 ms 11596 KB Output is correct
50 Correct 77 ms 11716 KB Output is correct
51 Correct 2 ms 6492 KB Output is correct
52 Correct 19 ms 8280 KB Output is correct
53 Correct 89 ms 11348 KB Output is correct
54 Correct 81 ms 11336 KB Output is correct
55 Correct 76 ms 11604 KB Output is correct
56 Correct 56 ms 11604 KB Output is correct
57 Correct 52 ms 11348 KB Output is correct
58 Correct 80 ms 11856 KB Output is correct
59 Correct 20 ms 8284 KB Output is correct
60 Correct 51 ms 10744 KB Output is correct
61 Correct 53 ms 11148 KB Output is correct
62 Correct 91 ms 11408 KB Output is correct
63 Correct 61 ms 11344 KB Output is correct
64 Correct 86 ms 11588 KB Output is correct
65 Correct 68 ms 11912 KB Output is correct
66 Correct 60 ms 11864 KB Output is correct
67 Correct 47 ms 13368 KB Output is correct
68 Correct 68 ms 13372 KB Output is correct
69 Correct 58 ms 13412 KB Output is correct
70 Correct 52 ms 13364 KB Output is correct