Submission #217939

#	Time	Username	Problem	Language	Result	Execution time	Memory
217939		perveevm	Duathlon (APIO18_duathlon)	C++14	0 / 100	81 ms	12664 KiB

count_triplets

// #pragma comment(linker, "/stack:200000000")
// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
// #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>

#ifdef PERVEEVM_LOCAL
    #define debug(x) std::cerr << (#x) << ":\t" << (x) << std::endl
#else
    #define debug(x) 238;
#endif

#define fastIO std::ios_base::sync_with_stdio(false); std::cin.tie(0); std::cout.tie(0)
#define NAME "File"

using ll = long long;
using ld = long double;

#ifdef PERVEEVM_LOCAL
    std::mt19937 rnd(238);
#else
    std::mt19937 rnd(std::chrono::high_resolution_clock::now().time_since_epoch().count());
#endif

const double PI = atan2(0.0, -1.0);
const int INF = 0x3f3f3f3f;
const ll LINF = (ll)2e18;
const int N = 200100;

std::vector<int> g[N];
bool used[N];
int sz = 0;

void dfs(int v) {
    used[v] = true;
    ++sz;

    for (auto to : g[v]) {
        if (!used[to]) {
            dfs(to);
        }
    }
}

void run() {
    int n, m;
    scanf("%d%d", &n, &m);

    for (int i = 0; i < m; ++i) {
        int from, to;
        scanf("%d%d", &from, &to);

        g[from - 1].push_back(to - 1);
        g[to - 1].push_back(from - 1);
    }

    ll ans = 0;
    for (int i = 0; i < n; ++i) {
        if (!used[i]) {
            sz = 0;
            dfs(i);

            ans += 1ll * sz * (sz - 1) * (sz - 2) / 3;
        }
    }

    printf("%lld\n", ans);
}

int main(void) {
    // freopen(NAME".in", "r", stdin);
    // freopen(NAME".out", "w", stdout);

    auto start = std::chrono::high_resolution_clock::now();
    run();
    auto end = std::chrono::high_resolution_clock::now();

    #ifdef PERVEEVM_LOCAL
        std::cerr << "Execution time: "
                  << std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count()
                  << " ms" << std::endl;
    #endif

    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:75:10: warning: variable 'start' set but not used [-Wunused-but-set-variable]
     auto start = std::chrono::high_resolution_clock::now();
          ^~~~~
count_triplets.cpp:77:10: warning: variable 'end' set but not used [-Wunused-but-set-variable]
     auto end = std::chrono::high_resolution_clock::now();
          ^~~
count_triplets.cpp: In function 'void run()':
count_triplets.cpp:48:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
count_triplets.cpp:52:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &from, &to);
         ~~~~~^~~~~~~~~~~~~~~~~~~~

• 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