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답안 #442488

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
442488 2021-07-08T00:42:54 Z Ozy The Xana coup (BOI21_xanadu) C++17
100 / 100
 99 ms 21932 KB 
#include <iostream>
#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for (int i = (a); i <= (b); i++)
#define repa(i,a,b) for (int i = (a); i >= (b); i--)
#define lli long long int
#define debug(a) cout << #a << " = " << a << endl
#define debugsl(a) cout << #a << " = " << a << ", "

#define MAX 100000

#define apagado 0
#define prendido 1
#define nousado 0
#define usado 1
#define impar 1
#define par 0

#define IMP 200000ll

lli n,a,b;
lli dp[2][2][MAX+2], inicial[MAX+2];
vector<lli> hijos[MAX+2];

lli obtenminimo(vector<int> &nodos, int estado, int paridadusados){
    lli dif = IMP, usados = 0, res = 0;
    for(auto nodo : nodos){
        // SI ES IMPOSIBLE DEJAR EL NODO EN EL ESTADO QUE QUIERES, ENTONCES ES IMPOSIBLE
        if (dp[estado][usado][nodo] >= IMP && dp[estado][nousado][nodo] >= IMP) return IMP;
        if (dp[estado][usado][nodo] < dp[estado][nousado][nodo]){
            ++usados;
            res += dp[estado][usado][nodo];
            if (dp[estado][nousado][nodo] < IMP) dif = min(dif, dp[estado][nousado][nodo] - dp[estado][usado][nodo]);
        }
        else{
            res += dp[estado][nousado][nodo];
            if (dp[estado][usado][nodo] < IMP) dif = min(dif, dp[estado][usado][nodo] - dp[estado][nousado][nodo]);
        }
    }

    usados &= 1; // SACA LA PARIDAD DE LOS USADOS
    if (paridadusados == usados) return res; // EL MINIMO ERA USANDO LOS QUE QUERIAS.
    else if (dif != IMP) return res + dif;   // TENIAS QUE USAR UNO MENOS O MAS, PERO SI HABIA UNA OPCION PARA CAMBIAR
    else return IMP;                         // NO HABIA OPCION PARA CAMBIAR
}

void DFS(lli pos, lli padre) {
    if (pos != 1 && hijos[pos].size() == 1 && inicial[pos] == apagado){
        // SI ES UNA HOJA APAGADA
        dp[apagado][usado][pos] = dp[prendido][nousado][pos] = IMP;
        dp[apagado][nousado][pos] = 0;
        dp[prendido][usado][pos] = 1;
        return;
    }

    if (pos != 1 && hijos[pos].size() == 1 && inicial[pos] == prendido){
        // SI ES UNA HOJA PRENDIDA
        dp[prendido][usado][pos] = dp[apagado][nousado][pos] = IMP;
        dp[prendido][nousado][pos] = 0;
        dp[apagado][usado][pos] = 1;
        return;
    }

    vector<int> nodos;
    for(auto h : hijos[pos]){
        if (h == padre) continue;
        DFS(h, pos);
        nodos.push_back(h);
    }

    // LLENA CADA UNO DE LOS CUATRO CASOS
    dp[apagado][usado][pos] = obtenminimo(nodos, prendido, (inicial[pos] == apagado) ? impar : par) + 1;
    dp[apagado][nousado][pos] = obtenminimo(nodos, apagado, (inicial[pos] == apagado) ? par : impar);
    dp[prendido][usado][pos] = obtenminimo(nodos, prendido, (inicial[pos] == prendido) ? impar : par) + 1;
    dp[prendido][nousado][pos] = obtenminimo(nodos, apagado, (inicial[pos] == prendido) ? par: impar);

}

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

    cin >> n;
    rep(i,1,n-1) {
        cin >> a >> b;
        hijos[a].push_back(b);
        hijos[b].push_back(a);
    }
    rep(i,1,n) cin >> inicial[i];

    DFS(1,0);
    a = min(dp[apagado][usado][1], dp[apagado][nousado][1]);

    if (a == IMP) cout << "impossible";
    else cout << a;
}

Subtask #1
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2572 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2572 KB Output is correct
6 Correct 3 ms 2692 KB Output is correct
7 Correct 2 ms 2688 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 2680 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 2676 KB Output is correct
16 Correct 2 ms 2636 KB Output is correct

Subtask #3
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 68 ms 20480 KB Output is correct
2 Correct 76 ms 21624 KB Output is correct
3 Correct 83 ms 21932 KB Output is correct

Subtask #4
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 73 ms 20464 KB Output is correct
2 Correct 76 ms 21572 KB Output is correct
3 Correct 80 ms 21876 KB Output is correct
4 Correct 71 ms 10944 KB Output is correct
5 Correct 74 ms 11720 KB Output is correct
6 Correct 80 ms 11812 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 22 ms 5708 KB Output is correct
9 Correct 79 ms 11552 KB Output is correct
10 Correct 81 ms 11716 KB Output is correct
11 Correct 82 ms 12100 KB Output is correct
12 Correct 84 ms 12516 KB Output is correct
13 Correct 83 ms 11628 KB Output is correct
14 Correct 99 ms 12208 KB Output is correct

Subtask #5
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2572 KB Output is correct
6 Correct 3 ms 2692 KB Output is correct
7 Correct 2 ms 2688 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 2680 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 2676 KB Output is correct
16 Correct 2 ms 2636 KB Output is correct
17 Correct 68 ms 20480 KB Output is correct
18 Correct 76 ms 21624 KB Output is correct
19 Correct 83 ms 21932 KB Output is correct
20 Correct 73 ms 20464 KB Output is correct
21 Correct 76 ms 21572 KB Output is correct
22 Correct 80 ms 21876 KB Output is correct
23 Correct 71 ms 10944 KB Output is correct
24 Correct 74 ms 11720 KB Output is correct
25 Correct 80 ms 11812 KB Output is correct
26 Correct 2 ms 2636 KB Output is correct
27 Correct 22 ms 5708 KB Output is correct
28 Correct 79 ms 11552 KB Output is correct
29 Correct 81 ms 11716 KB Output is correct
30 Correct 82 ms 12100 KB Output is correct
31 Correct 84 ms 12516 KB Output is correct
32 Correct 83 ms 11628 KB Output is correct
33 Correct 99 ms 12208 KB Output is correct
34 Correct 2 ms 2636 KB Output is correct
35 Correct 2 ms 2636 KB Output is correct
36 Correct 2 ms 2636 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 2636 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 2672 KB Output is correct
45 Correct 74 ms 21856 KB Output is correct
46 Correct 68 ms 21600 KB Output is correct
47 Correct 68 ms 21904 KB Output is correct
48 Correct 67 ms 10948 KB Output is correct
49 Correct 79 ms 11732 KB Output is correct
50 Correct 86 ms 11896 KB Output is correct
51 Correct 2 ms 2636 KB Output is correct
52 Correct 22 ms 5628 KB Output is correct
53 Correct 81 ms 11504 KB Output is correct
54 Correct 84 ms 11708 KB Output is correct
55 Correct 80 ms 12216 KB Output is correct
56 Correct 94 ms 12520 KB Output is correct
57 Correct 85 ms 11608 KB Output is correct
58 Correct 78 ms 12156 KB Output is correct
59 Correct 21 ms 5572 KB Output is correct
60 Correct 66 ms 10584 KB Output is correct
61 Correct 74 ms 11460 KB Output is correct
62 Correct 77 ms 11612 KB Output is correct
63 Correct 78 ms 11588 KB Output is correct
64 Correct 80 ms 11716 KB Output is correct
65 Correct 58 ms 12076 KB Output is correct
66 Correct 58 ms 12032 KB Output is correct
67 Correct 52 ms 12696 KB Output is correct
68 Correct 51 ms 12708 KB Output is correct
69 Correct 62 ms 12692 KB Output is correct
70 Correct 52 ms 12692 KB Output is correct