Submission #1165655

#	Time	Username	Problem	Language	Result	Execution time	Memory
1165655		InvMOD	Training (IOI07_training)	C++20	100 / 100	4 ms	840 KiB

training

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define REV(i, a, b) for(int i = (a); i >= (b); i--)
#define dbg(x) "[" #x " = " << (x) << "]"
///#define int long long

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}

const int N = 2e5+5;
const ll MOD = 1e9+7;
const ll INF = 1e18;

struct Edge{
    int u,v; ll w;
    Edge(int u = 0, int v = 0, ll w = 0): u(u), v(v), w(w) {}

    bool operator < (const Edge& q) const{
        return w < q.w;
    };
};

void solve()
{
    int n,m; cin >> n >> m;

    vector<Edge> E(m + 1);
    FOR(i, 1, m){
        int u,v,w; cin >> u >> v >> w;
        E[i] = Edge(u, v, w);
    }

    sort(1 + all(E));

    vector<vector<int>> adj(n + 1, vector<int>());
    FOR(i, 1, m){
        if(!E[i].w){
            int u = E[i].u, v = E[i].v;
            adj[u].pb(v), adj[v].pb(u);
        }
    }

    const int lg = 12;

    vector<int> h(n + 1), idChild(n + 1);

    vector<vector<int>> child(n + 1, vector<int>());
    vector<vector<int>> par(lg, vector<int>(n + 1));

    function<void(int,int)> preDFS = [&](int x, int p) -> void{
        for(int v : adj[x])if(v != p) child[x].push_back(v);

        for(int j = 0; j < sz(child[x]); j++){
            int v = child[x][j];
            par[0][v] = x;
            for(int i = 1; i < lg; i++){
                par[i][v] = par[i - 1][par[i - 1][v]];
            }
            h[v] = h[x] + 1;
            idChild[v] = j;
            preDFS(v, x);
        }
        return;
    };

    preDFS(1, -1);

    auto bjump = [&](int u, int dist) -> int{
        for(int i = lg - 1; i >= 0; i--){
            if(dist >> i & 1){
                u = par[i][u];
            }
        }
        return u;
    };

    auto get_LCA = [&](int u, int v) -> int{
        if(h[u] < h[v]) swap(u, v);

        u = bjump(u, h[u] - h[v]);
        if(u == v) return v;

        for(int i = lg - 1; i >= 0; i--){
            if(par[i][u] != par[i][v]){
                u = par[i][u];
                v = par[i][v];
            }
        }
        return par[0][v];
    };

    vector<vector<Edge>> Query(n + 1, vector<Edge>());

    ll total = 0;
    FOR(i, 1, m){
        if(E[i].w){
            int u = E[i].u, v = E[i].v;
            int lca = get_LCA(u, v);

            int dist = h[u] + h[v] - 2 * h[lca];
            if(!(dist & 1)){
                Query[lca].push_back(E[i]);
                //cout << u <<" " << v <<" " << E[i].w << "\n";
            }
        }
        total = total + E[i].w;
    }

    vector<vector<ll>> dp(n + 1, vector<ll>());

    auto fmask = [&](int u) -> int{
        return (1 << sz(child[u])) - 1;
    };

    auto calc = [&](int x, int fa) -> ll{
        if(x == fa) return 0;

        ll answer = dp[x][fmask(x)];
        while(par[0][x] != fa){
            int u = par[0][x];

            int curID = fmask(u) ^ (1 << idChild[x]);
            answer = answer + dp[u][curID];

            x = u;
        }
        return answer;
    };

    function<void(int,int)> calc_dp = [&](int x, int p) -> void{
        dp[x].assign(fmask(x) + 1, 0);
        for(int v : child[x]){
            calc_dp(v, x);
            for(int msk = (1 << idChild[v]); msk <= fmask(x); msk++, msk |= (1 << idChild[v])){
                dp[x][msk] = max(dp[x][msk], dp[x][msk ^ (1 << idChild[v])] + dp[v][fmask(v)]);
            }
        }

        for(Edge& e : Query[x]){
            int u = e.u, v = e.v;

            ll tmp = e.w;

            int maskChoosed = 0;
            if(u != x){
                tmp = tmp + calc(u, x);

                int paru = bjump(u, h[u] - h[x] - 1);
                maskChoosed = maskChoosed | (1 << idChild[paru]);
            }
            if(v != x){
                tmp = tmp + calc(v, x);

                int parv = bjump(v, h[v] - h[x] - 1);
                maskChoosed = maskChoosed | (1 << idChild[parv]);
            }

            for(int msk = maskChoosed; msk <= fmask(x); msk++, msk |= maskChoosed){
                dp[x][msk] = max(dp[x][msk], dp[x][msk ^ maskChoosed] + tmp);
            }
        }
        return;
    };

    calc_dp(1, -1);

    cout << total - dp[1][fmask(1)] << "\n";
}

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

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP","r",stdin);
        freopen(name".OUT","w",stdout);
    }

    int t = 1; //cin >> t;
    while(t--) solve();
    return 0;
}

Compilation message (stderr)

training.cpp: In function 'int main()':
training.cpp:192:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  192 |         freopen(name".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
training.cpp:193:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  193 |         freopen(name".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 7 / 7
• Subtask 5: 9 / 9
• Subtask 6: 9 / 9
• Subtask 7: 9 / 9
• Subtask 8: 9 / 9
• Subtask 9: 9 / 9
• Subtask 10: 9 / 9
• Subtask 11: 9 / 9