Submission #1096938

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096938		andrei_iorgulescu	The Xana coup (BOI21_xanadu)	C++14	100 / 100	109 ms	27476 KiB

xanadu

#include <bits/stdc++.h>

using namespace std;

#define int long long

int inf = 1e9;

int n, v[100005];
vector<int> g[100005], f[100005];
bool viz[100005];
int dp[100005][2][2];

void dfs(int nod)
{
    viz[nod] = true;
    for (auto it : g[nod])
        if (!viz[it])
            f[nod].push_back(it), dfs(it);
}

void solve(int nod)
{
    for (auto fiu : f[nod])
        solve(fiu);
    for (int sf = 0; sf < 2; sf++)
    {
        for (int cf = 0; cf < 2; cf++)
        {
            vector<vector<int>> d(f[nod].size() + 1);
            for (int i = 0; i < d.size(); i++)
                d[i].resize(2);
            d[0][0] = cf;
            d[0][1] = inf;
            for (int i = 1; i < d.size(); i++)
            {
                int fiu = f[nod][i - 1];
                for (int cr = 0; cr < 2; cr++)
                {
                    d[i][cr] = inf;
                    for (int uu = 0; uu < 2; uu++)
                        d[i][cr] = min(d[i][cr], d[i - 1][cr ^ uu] + dp[fiu][cf][uu]);
                }
            }
            dp[nod][sf][cf] = d[d.size() - 1][sf ^ cf ^ v[nod]];
        }
    }
}

signed main()
{
    cin >> n;
    for (int i = 1; i < n; i++)
    {
        int x, y;
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for (int i = 1; i <= n; i++)
        cin >> v[i];
    dfs(1);
    solve(1);
    int kk = min(dp[1][0][0], dp[1][0][1]);
    if (kk >= inf)
        cout << "impossible";
    else
        cout << kk;
    return 0;
}

Compilation message (stderr)

xanadu.cpp: In function 'void solve(long long int)':
xanadu.cpp:31:31: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::vector<long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |             for (int i = 0; i < d.size(); i++)
      |                             ~~^~~~~~~~~~
xanadu.cpp:35:31: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::vector<long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |             for (int i = 1; i < d.size(); i++)
      |                             ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 10 / 10
• Subtask 4: 40 / 40
• Subtask 5: 30 / 30