Submission #243713

#	Time	Username	Problem	Language	Result	Execution time	Memory
243713		SamAnd	Roadside Advertisements (NOI17_roadsideadverts)	C++17	100 / 100	90 ms	16632 KiB

roadsideadverts

#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define fi first
#define se second
typedef long long ll;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
mt19937 rnf(2106);
const int N = 100005;

int n;
vector<int> g[N], gd[N];

const int m = 18;
int p[N][m];
int d[N];

int tin[N], tout[N], ti;

void dfs(int x, int p0)
{
    tin[x] = ++ti;
    p[x][0] = p0;
    for (int i = 1; i < m; ++i)
        p[x][i] = p[p[x][i - 1]][i - 1];
    for (int i = 0; i < g[x].size(); ++i)
    {
        int h = g[x][i];
        if (h == p0)
            continue;
        d[h] = d[x] + gd[x][i];
        dfs(h, x);
    }
    tout[x] = ti;
}

bool isp(int x, int y)
{
    return (tin[x] <= tin[y] && tout[y] <= tout[x]);
}

int lca(int x, int y)
{
    if (isp(x, y))
        return x;
    if (isp(y, x))
        return y;
    for (int i = m - 1; i >= 0; --i)
    {
        if (!isp(p[x][i], y))
            x = p[x][i];
    }
    return p[x][0];
}

bool so(int x, int y)
{
    return tin[x] < tin[y];
}

int dist(int x, int y)
{
    return d[x] + d[y] - 2 * d[lca(x, y)];
}

void solv()
{
    scanf("%d", &n);
    for (int i = 0; i < n - 1; ++i)
    {
        int x, y, d;
        scanf("%d%d%d", &x, &y, &d);
        g[x].push_back(y);
        g[y].push_back(x);
        gd[x].push_back(d);
        gd[y].push_back(d);
    }
    dfs(0, 0);
    int qq;
    scanf("%d", &qq);
    while (qq--)
    {
        int x[5];
        for (int i = 0; i < 5; ++i)
        {
            scanf("%d", &x[i]);
        }
        sort(x, x + 5, so);
        int ans = 0;
        ans += dist(lca(x[0], x[4]), x[0]);
        for (int i = 0; i < 5 - 1; ++i)
            ans += dist(x[i], x[i + 1]);
        ans += dist(lca(x[0], x[4]), x[4]);
        printf("%d\n", ans / 2);
    }
}

int main()
{
    #ifdef SOMETHING
    freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    #endif // SOMETHING
    //ios_base::sync_with_stdio(false), cin.tie(0);
    solv();
    return 0;
}

//while ((double)clock() / CLOCKS_PER_SEC <= 0.9){}

Compilation message (stderr)

roadsideadverts.cpp: In function 'void dfs(int, int)':
roadsideadverts.cpp:28:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[x].size(); ++i)
                     ~~^~~~~~~~~~~~~
roadsideadverts.cpp: In function 'void solv()':
roadsideadverts.cpp:70:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
roadsideadverts.cpp:74:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d", &x, &y, &d);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~
roadsideadverts.cpp:82:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &qq);
     ~~~~~^~~~~~~~~~~
roadsideadverts.cpp:88:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d", &x[i]);
             ~~~~~^~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 23 / 23
• Subtask 3: 40 / 40
• Subtask 4: 30 / 30