Submission #1102574

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102574		thaibeo123	Race (IOI11_race)	C++14	Compilation error	0 ms	0 KiB

race

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

#define ll long long
#define fi first
#define se second
#define pb push_back

const int N = 1e6 + 5;

int n, k, mx, ans = 1e9;
bool centroid[N];
int dp[N], sz[N];
vector<pair<int, int>> g[N];

void input() {
    cin >> n >> k;
    for (int i = 1; i < n; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        ++u, ++v;
        g[u].pb({v, w});
        g[v].pb({u, w});
    }
}

int dfs(int u, int par, int h) {
    sz[u] = 1;
    mx = max(mx, h);
    for (auto b : g[u]) {
        int v = b.fi;
        if (v != par && !centroid[v]) {
            sz[u] += dfs(v, u, h + 1);
        }
    }
    return sz[u];
}

int find_centroid(int u, int par, int n) {
    for (auto b : g[u]) {
        int v = b.fi;
        if (v != par && !centroid[v] && sz[v] > n / 2) {
            return find_centroid(v, u, n);
        }
    }
    return u;
}

void count_path(int u, int par, int h, int e) {
    if (h <= k) {
        ans = min(ans, e + dp[k - h]);
    }
    //cout << u << " " << h << " " << e << " " << k - h << " " << dp[k - h] << "\n";
    for (auto b : g[u]) {
        int v = b.fi, w = b.se;
        if (v != par && !centroid[v] && h + w <= k) {
            count_path(v, u, h + w, e + 1);
        }
    }
}

void update(int u, int par, int h, int e) {
    dp[h] = min(dp[h], e);
    for (auto b : g[u]) {
        int v = b.fi, w = b.se;
        if (v != par && !centroid[v] && h + w <= k) {
            count_path(v, u, h + w, e + 1);
        }
    }
}

void solve_centroid(int u) {
    mx = 0;
    int n = dfs(u, 0, 0);
    int c = find_centroid(u, 0, n);

    centroid[c] = 1;
    for (int i = 1; i <= mx * 10; ++i) {
        dp[i] = 1e9;
    }
    dp[0] = 0;
    for (auto b : g[c]) {
        int v = b.fi;
        int w = b.se;
        if (!centroid[v] && w <= k) {
            count_path(v, c, w, 1);
            update(v, c, w, 1);
        }
    }
    for (auto b : g[c]) {
        int v = b.fi;
        if (!centroid[v]) {
            solve_centroid(v);
        }
    }
}

void solve() {
    solve_centroid(1);
    cout << (ans == 1e9 ? -1 : ans);
}

int main() {
    cin.tie(0)->sync_with_stdio(0);

    input();
    solve();

    return 0;
}

Compilation message (stderr)

/usr/bin/ld: /tmp/ccS7ICO4.o: in function `main':
race.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/cciobQU6.o:grader.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/cciobQU6.o: in function `main':
grader.cpp:(.text.startup+0x28): undefined reference to `best_path(int, int, int (*) [2], int*)'
collect2: error: ld returned 1 exit status