Submission #1070332

#	Time	Username	Problem	Language	Result	Execution time	Memory
1070332		Boycl07	Election Campaign (JOI15_election_campaign)	C++17	100 / 100	86 ms	29028 KiB

election_campaign

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

typedef long long ll;

#define rep(i, n) for(int i = 1; (i) <= (n); ++i)
#define forn(i, l, r) for(int i = (l); i <= (r); ++i)
#define ford(i, r, l) for(int i = (r); i >= (l); --i)
#define FOR(i, n) for(int i = 0; i < (n); ++i)
#define FORD(i, n) for(int i = ((n) - 1); i >= 0; --i)
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define endl "\n"
#define task "FFILL"
#define sz(a) int(a.size())
#define C(x, y) make_pair(x, y)
#define all(a) (a).begin(), (a).end()
#define bit(i, mask) (mask >> i & 1)

template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }


const int N = 1e5 + 3;
const int LIM = (1 << 16) + 3;
const ll INF = 1e18 + 1;
const int LOG = 16;

int n, q;
vector<int> g[N];
vector<array<int, 3>> f[N];
int tin[N], tout[N], up[N][LOG + 1], timedfs = 0;
int val[N];
int dp[N];
int bit[N];

void update(int u, int v)
{
    for(; u <= n; u += u & -u) bit[u] += v;
}

int get(int u)
{
    int res = 0;
    for(; u; u -= u & -u) res += bit[u];
    return res;
}

void pre_dfs(int u, int p = 1)
{
    up[u][0] = p;
    tin[u] = ++timedfs;
    forn(i, 1, LOG) up[u][i] = up[up[u][i - 1]][i - 1];
    for(int v : g[u]) if(v != p) pre_dfs(v, u);
    tout[u] = timedfs;
}

bool isAnc(int u, int v) {return tin[u] <= tin[v] && tout[v] <= tout[u];}

int lca(int u, int v)
{
    if(isAnc(u, v)) return u;
    if(isAnc(v, u)) return v;
    ford(i, LOG, 0) if(!isAnc(up[u][i], v)) u = up[u][i];
    return up[u][0];
}

void dfs(int u, int p = 1)
{
    int sum = 0, best = 0;
    for(int v : g[u]) if(v != p) dfs(v, u), sum += dp[v];
    for(auto &[x, y, c] : f[u])
    {
        int val = c + (x == u ? 0 : get(tin[x]))
                    + (y == u ? 0 : get(tin[y]));
        maximize(best, val);
    }
    dp[u] = sum + best;
    update(tin[u], -best); update(tout[u] + 1, best);
}

void solve()
{
    cin >> n;
    rep(i, n - 1)
    {
        int u, v;
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }

    pre_dfs(1);
    cin >> q;
    rep(i, q)
    {
        int u, v, c;
        cin >> u >> v >> c;
        f[lca(u, v)].pb({u, v, c});
    }
    dfs(1);
    cout << dp[1];
}

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

    int TC = 1;

    if(fopen("note.inp", "r"))
    {
        freopen("note.inp", "r", stdin);
        freopen("note.out", "w", stdout);
    }


    while(TC--)
    {
        solve();
    }

    return 0;
}

Compilation message (stderr)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:117:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  117 |         freopen("note.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
election_campaign.cpp:118:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  118 |         freopen("note.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 30 / 30
• Subtask 5: 10 / 10
• Subtask 6: 40 / 40