Submission #512502

#	Time	Username	Problem	Language	Result	Execution time	Memory
512502		Killer2501	Election Campaign (JOI15_election_campaign)	C++14	100 / 100	253 ms	37192 KiB

election_campaign

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define ull unsigned long long
#define pb push_back
#define pll pair<ll, ll>
#define pii pair<int, int>
#define fi first
#define se second
using namespace std;
const int N = 2e5+5;
const int M = (1<<17);
const ll inf = 1e15;
const int mod = 1e9+7;
int n, t, k, a[N], c[N], d[N], m, P[N][19], h[N], in[N], out[N];
ll ans, tong, b[N], dp[N], fe[N];
string s;
struct node
{
    int val, x, y;
    node(){}
    node(int _val, int _x, int _y)
    {
        val = _val;
        x = _x;
        y = _y;
    }
    bool operator < (const node& u) const
    {
        return x > u.x;
    }
};
vector<node> g[N];
vector<int>  adj[N];
void add(int id, ll x)
{
    for(; id <= n; id += id & -id)fe[id] += x;
}
void add(int l, int r, ll x)
{
    add(l, x);
    add(r+1, -x);
}
ll get(int id)
{
    ll total = 0;
    for(; id; id -= id & -id)total += fe[id];
    return total;
}
void dfs(int u, int p = 0)
{
    in[u] = ++k;
    for(int v: adj[u])
    {
        if(v == p)continue;
        h[v] = h[u]+1;
        P[v][0] = u;
        for(int i = 1; i <= 18; i ++)P[v][i] = P[P[v][i-1]][i-1];
        dfs(v, u);
    }
    out[u] = k;
}
int lca(int u, int v)
{
    if(h[u] < h[v])swap(u, v);
    int log = log2(h[u]);
    for(int i = log; i >= 0; i --)if(h[u] >= h[v]+(1<<i))u = P[u][i];
    if(u == v)return u;
    for(int i = log; i >= 0; i --)
    {
        if(P[u][i] && P[u][i] != P[v][i])
        {
            u = P[u][i];
            v = P[v][i];
        }
    }
    return P[u][0];
}
void cal(int u, int p = 0)
{
    for(int v: adj[u])
    {
        if(v == p)continue;
        cal(v, u);
        add(in[u], out[u], dp[v]);
        add(in[v], out[v], -dp[v]);
    }

    dp[u] = get(in[u]) - get(in[p]);
    for(node t: g[u])
    {
        dp[u] = max(dp[u], get(in[t.x]) + get(in[t.y]) - get(in[u]) - get(in[p]) + t.val);
    }
}
void sol()
{
    cin >> n;
    for(int i = 1; i < n; i ++)
    {
        int x, y;
        cin >> x >> y;
        adj[x].pb(y);
        adj[y].pb(x);
    }
    dfs(1);
    cin >> m;
    while(m -- > 0)
    {
        int x, y, z;
        cin >> x >> y >> k;
        z = lca(x, y);
        g[z].pb(node(k, x, y));
    }

    cal(1);
    cout << dp[1];
}
int main()
{
    cin.tie(0);
    cout.tie(0);
    ios_base::sync_with_stdio(0);
    #define task "test"
    if(fopen(task".inp", "r"))
	{
		freopen(task".inp", "r", stdin);
		freopen(task".out", "w", stdout);
    }
    int ntest = 1;
    //cin >> ntest;
    while(ntest -- > 0)
    sol();
}

Compilation message (stderr)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:126:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  126 |   freopen(task".inp", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
election_campaign.cpp:127:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  127 |   freopen(task".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