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답안 #415208

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
415208 2021-05-31T16:49:20 Z tengiz05 The Xana coup (BOI21_xanadu) C++17
100 / 100
 154 ms 39368 KB 
#include <bits/stdc++.h>
using i64 = long long;
constexpr int N = 1e5;
i64 dp[N][2][2], a[N];
std::vector<int> e[N];
struct opt{
    std::vector<i64> pr;
    i64 sum;
    opt(std::vector<i64> a, std::vector<i64> b) : pr(a.size() + 1), sum(0) {
        std::vector<i64> v;
        for (int i = 0; i < int(a.size()); i++) {
            v.push_back(-a[i] + b[i]);
        }
        sort(v.begin(), v.end());
        for (int i = 0; i < int(v.size()); i++) {
            sum += a[i];
            pr[i + 1] = pr[i] + v[i];
        }
    }
    i64 odd() {
        i64 res = 1e9;
        for (int i = 1; i < pr.size(); i += 2) {
            res = std::min(res, pr[i] + sum);
        }
        return res;
    }
    i64 even() {
        i64 res = 1e9;
        for (int i = 0; i < pr.size(); i += 2) {
            res = std::min(res, pr[i] + sum);
        }
        return res;
    }
};
void dfs(int u, int p) {
    if (e[u].size() == 1 && p != -1) {
        if (a[u] == 0) {
            dp[u][0][0] = 0;
            dp[u][1][1] = 1;
        } else {
            dp[u][1][0] = 0;
            dp[u][0][1] = 1;
        }
        return;
    }
    std::vector<int> c;
    for (auto v : e[u]) {
        if (v == p) continue;
        dfs(v, u);
        c.push_back(v);
    }
    int k = c.size();
    if (k == 1) {
        int l = c[0];
        if (a[u] == 0) {
            dp[u][0][0] = dp[l][0][0];
            dp[u][0][1] = dp[l][1][1] + 1;
            dp[u][1][0] = dp[l][0][1];
            dp[u][1][1] = dp[l][1][0] + 1;
        } else {
            dp[u][1][0] = dp[l][0][0];
            dp[u][1][1] = dp[l][1][1] + 1;
            dp[u][0][0] = dp[l][0][1];
            dp[u][0][1] = dp[l][1][0] + 1;
        }
    } else {
        if (a[u] == 0) {
            {
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][0][0]);
                for (auto x : c) B.push_back(dp[x][0][1]);
                opt p(A, B);
                dp[u][0][0] = p.even();
            }{
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][1][0]);
                for (auto x : c) B.push_back(dp[x][1][1]);
                opt p(A, B);
                dp[u][0][1] = p.odd() + 1;
            }
            {
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][0][0]);
                for (auto x : c) B.push_back(dp[x][0][1]);
                opt p(A, B);
                dp[u][1][0] = p.odd();
            }{
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][1][0]);
                for (auto x : c) B.push_back(dp[x][1][1]);
                opt p(A, B);
                dp[u][1][1] = p.even() + 1;
            }
        } else {
            {
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][0][0]);
                for (auto x : c) B.push_back(dp[x][0][1]);
                opt p(A, B);
                dp[u][1][0] = p.even();
            }{
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][1][0]);
                for (auto x : c) B.push_back(dp[x][1][1]);
                opt p(A, B);
                dp[u][1][1] = p.odd() + 1;
            }
            {
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][0][0]);
                for (auto x : c) B.push_back(dp[x][0][1]);
                opt p(A, B);
                dp[u][0][0] = p.odd();
            }{
                std::vector<i64> A, B;
                for (auto x : c) A.push_back(dp[x][1][0]);
                for (auto x : c) B.push_back(dp[x][1][1]);
                opt p(A, B);
                dp[u][0][1] = p.even() + 1;
            }
        }
    }
}
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int n;
    std::cin >> n;
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        std::cin >> u >> v;
        u--;
        v--;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    for (int i = 0; i < n; i++) {
        std::cin >> a[i];
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < 2; j++) {
            for (int k = 0; k < 2; k++) {
                dp[i][j][k] = 1e9;
            }
        }
    }
    dfs(0, -1);
    i64 ans = 1e9;
    for (int j = 0; j < 2; j++) {
        ans = std::min(ans, dp[0][0][j]);
    }
    if (ans == 1e9) {
        std::cout << "impossible\n";
    } else {
        std::cout << ans << "\n";
    }
    return 0;
}

Compilation message

xanadu.cpp: In member function 'i64 opt::odd()':
xanadu.cpp:22:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |         for (int i = 1; i < pr.size(); i += 2) {
      |                         ~~^~~~~~~~~~~
xanadu.cpp: In member function 'i64 opt::even()':
xanadu.cpp:29:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |         for (int i = 0; i < pr.size(); i += 2) {
      |                         ~~^~~~~~~~~~~

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 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 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 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 3 ms 2636 KB Output is correct
7 Correct 3 ms 2636 KB Output is correct
8 Correct 2 ms 2636 KB Output is correct
9 Correct 2 ms 2636 KB Output is correct
10 Correct 3 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 3 ms 2636 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 3 ms 2636 KB Output is correct
16 Correct 3 ms 2636 KB Output is correct

Subtask #3
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 84 ms 39184 KB Output is correct
2 Correct 78 ms 38808 KB Output is correct
3 Correct 93 ms 39360 KB Output is correct

Subtask #4
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 83 ms 39188 KB Output is correct
2 Correct 89 ms 38720 KB Output is correct
3 Correct 92 ms 39316 KB Output is correct
4 Correct 112 ms 8900 KB Output is correct
5 Correct 137 ms 9572 KB Output is correct
6 Correct 134 ms 9668 KB Output is correct
7 Correct 3 ms 2636 KB Output is correct
8 Correct 34 ms 5196 KB Output is correct
9 Correct 123 ms 10052 KB Output is correct
10 Correct 108 ms 10052 KB Output is correct
11 Correct 107 ms 12136 KB Output is correct
12 Correct 126 ms 12540 KB Output is correct
13 Correct 138 ms 9156 KB Output is correct
14 Correct 137 ms 9660 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 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 3 ms 2636 KB Output is correct
7 Correct 3 ms 2636 KB Output is correct
8 Correct 2 ms 2636 KB Output is correct
9 Correct 2 ms 2636 KB Output is correct
10 Correct 3 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 3 ms 2636 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 3 ms 2636 KB Output is correct
16 Correct 3 ms 2636 KB Output is correct
17 Correct 84 ms 39184 KB Output is correct
18 Correct 78 ms 38808 KB Output is correct
19 Correct 93 ms 39360 KB Output is correct
20 Correct 83 ms 39188 KB Output is correct
21 Correct 89 ms 38720 KB Output is correct
22 Correct 92 ms 39316 KB Output is correct
23 Correct 112 ms 8900 KB Output is correct
24 Correct 137 ms 9572 KB Output is correct
25 Correct 134 ms 9668 KB Output is correct
26 Correct 3 ms 2636 KB Output is correct
27 Correct 34 ms 5196 KB Output is correct
28 Correct 123 ms 10052 KB Output is correct
29 Correct 108 ms 10052 KB Output is correct
30 Correct 107 ms 12136 KB Output is correct
31 Correct 126 ms 12540 KB Output is correct
32 Correct 138 ms 9156 KB Output is correct
33 Correct 137 ms 9660 KB Output is correct
34 Correct 2 ms 2636 KB Output is correct
35 Correct 2 ms 2636 KB Output is correct
36 Correct 3 ms 2636 KB Output is correct
37 Correct 2 ms 2636 KB Output is correct
38 Correct 3 ms 2636 KB Output is correct
39 Correct 2 ms 2636 KB Output is correct
40 Correct 3 ms 2636 KB Output is correct
41 Correct 2 ms 2636 KB Output is correct
42 Correct 3 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 83 ms 39220 KB Output is correct
46 Correct 96 ms 38716 KB Output is correct
47 Correct 96 ms 39368 KB Output is correct
48 Correct 115 ms 8956 KB Output is correct
49 Correct 120 ms 9568 KB Output is correct
50 Correct 120 ms 9672 KB Output is correct
51 Correct 3 ms 2636 KB Output is correct
52 Correct 35 ms 5196 KB Output is correct
53 Correct 117 ms 9756 KB Output is correct
54 Correct 116 ms 9992 KB Output is correct
55 Correct 100 ms 12100 KB Output is correct
56 Correct 106 ms 12564 KB Output is correct
57 Correct 131 ms 9276 KB Output is correct
58 Correct 154 ms 9684 KB Output is correct
59 Correct 33 ms 5068 KB Output is correct
60 Correct 97 ms 9068 KB Output is correct
61 Correct 117 ms 9800 KB Output is correct
62 Correct 153 ms 9972 KB Output is correct
63 Correct 119 ms 9924 KB Output is correct
64 Correct 117 ms 9904 KB Output is correct
65 Correct 83 ms 10220 KB Output is correct
66 Correct 83 ms 10180 KB Output is correct
67 Correct 112 ms 16316 KB Output is correct
68 Correct 83 ms 16364 KB Output is correct
69 Correct 81 ms 16360 KB Output is correct
70 Correct 74 ms 16340 KB Output is correct