Submission #793766

#	Time	Username	Problem	Language	Result	Execution time	Memory
793766		vjudge1	Tourism (JOI23_tourism)	C++17	28 / 100	5065 ms	13900 KiB

tourism

#ifdef Home
#define _GLIBCXX_DEBUG
#endif // Home

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int N = 100100;
const int LOGN = 17;

vector < int > adj[N];
int up[N][LOGN], depth[N], use[N], T, ans, C[N];

void dfs(int v, int p) {
    depth[v] = depth[p] + 1;
    up[v][0] = p;
    for(int i = 1; i < LOGN; ++ i) {
        up[v][i] = up[ up[v][i - 1] ][i - 1];
    }
    for(auto &u : adj[v]) {
        if(u != p) {
            dfs(u, v);
        }
    }
}

int slow_LCA(int a, int b) {
    if(depth[a] < depth[b]) {
        swap(a, b);
    }
    ans += use[a] != T;
    ans += use[b] != T;
    use[a] = T;
    use[b] = T;
    for(; depth[a] > depth[b];) {
        a = up[a][0];
        if(use[a] == T) {
            return b;
        }
        ++ ans;
        use[a] = T;
    }
    for(; a != b;) {
        a = up[a][0];
        b = up[b][0];
        if(a == b) {
            use[b] = T;
            ++ ans;
            return a;
        }
        ans += 2;
        use[a] = T;
        use[b] = T;
    }
    return b;
}

main() {
#ifdef Home
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif // Home
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    int n, m, q;
    cin >> n >> m >> q;
    for(int i = 1, a, b; i < n; ++ i) {
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    for(int i = 1; i <= m; ++ i) {
        cin >> C[i]; 
    }
    dfs(1, 1);
    for(int l, r, m; q --> 0;) {
        cin >> l >> r;
        ans = 1;
        m = C[l ++];
        use[m] = ++ T;
        for(; l <= r; ++ l) {
            m = slow_LCA(m, C[l]);
        }
        cout << ans << '\n';
    }
}

Compilation message (stderr)

tourism.cpp:62:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   62 | main() {
      | ^~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 0 / 7
• Subtask 4: 18 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 41