Submission #1173326

#	Time	Username	Problem	Language	Result	Execution time	Memory
1173326		Muhammet	Duathlon (APIO18_duathlon)	C++20	0 / 100	640 ms	1114112 KiB

count_triplets

#include "bits/stdc++.h"

using namespace std;
 
#define ll long long
#define SZ(s) (int)s.size()

const int N = 5e3 + 5;
const int M = 1e9 + 7;

int b[N], n, m, ans, h[N], p[N], sp[N][25];

vector <int> v[N];

void dfs(int x, int y) {
    h[x] = h[y] + 1;
    p[x] = y;
    for(auto i : v[x]) {
        if(i == y) continue;
        dfs(i, x);
    }
}

int lca(int x, int y) {
    if(h[x] < h[y]) swap(x, y);
    for(int i = 20; i >= 0; i--) {
        if(h[sp[x][i]] >= h[y]) x = sp[x][i];
    }
    if(x == y) return x;
    for(int i = 20; i >= 0; i--) {
        if(sp[x][i] != sp[y][i]) x = sp[x][i], y = sp[y][i];
    }
    return p[x];
}

int f(int x, int y) {
    return max(0, h[x] + h[y] - 2 * h[lca(x, y)] - 1);
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(nullptr);

    cin >> n >> m;
    vector <int> v1, v2;
    for(int i = 1; i <= m; i++) {
        int u1, u2;
        cin >> u1 >> u2;
        v[u1].push_back(u2);
        v[u2].push_back(u1);
    }

    dfs(1, 0);

    for(int i = 1; i <= n; i++) {
        sp[i][0] = p[i];
    }

    for(int j = 1; j <= 20; j++) {
        for(int i = 1; i <= n; i++) {
            sp[i][j] = sp[sp[i][j-1]][j-1];
        }
    }

    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            ans += max(0, f(i, j));
        }
    }

    cout << ans;

    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10