Submission #501572

#	Time	Username	Problem	Language	Result	Execution time	Memory
501572		kaxzert	Duathlon (APIO18_duathlon)	C++17	49 / 100	71 ms	25896 KiB

count_triplets

/**
      ⚡⚡  ⚡⚡      ⚡⚡⚡     ⚡⚡  ⚡⚡  ⚡⚡⚡⚡⚡⚡   ⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡⚡
      ⚡⚡ ⚡⚡      ⚡⚡⚡⚡     ⚡⚡⚡⚡      ⚡⚡      ⚡⚡       ⚡⚡    ⚡⚡  ⚡⚡⚡⚡⚡⚡
      ⚡⚡⚡⚡      ⚡⚡  ⚡⚡      ⚡⚡      ⚡⚡       ⚡⚡⚡⚡⚡   ⚡⚡⚡⚡⚡⚡     ⚡⚡
      ⚡⚡ ⚡⚡    ⚡⚡⚡⚡⚡⚡     ⚡⚡     ⚡⚡         ⚡⚡       ⚡⚡  ⚡⚡       ⚡⚡
      ⚡⚡  ⚡⚡  ⚡⚡     ⚡⚡  ⚡⚡ ⚡⚡  ⚡⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡    ⚡⚡   ⚡⚡     ⚡⚡
**/

#include<bits/stdc++.h>

using namespace std;

#define fto(i, a, b) for(int i = a; i <= b; ++i)
#define fdto(i, a, b) for(int i = a; i >= b; --i)
#define bugarr(a, i, j) cout << #a << "{" << i << "..." << j << "}:"; fto(k, i, j-1) cout << a[k] << ", "; cout << a[j] << endl;
#define ll long long
#define db double
#define ldb long double
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define vt vector
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define trav(i, a) for(auto &i : a)
#define sz(a) (ll)a.size()
#define pi(a, b) pair<a, b>
#define fast ios::sync_with_stdio(false); cin.tie(0)

string to_bit(int n) {
    string res = "";
    while(n > 0) {
        res += to_string(n&1);
        n >>= 1;
    }
    return res;
}


void setIO(string s) {
    if (sz(s) != 0) {
        freopen((s+".inp").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

void setIOusaco(string s) {
    if (sz(s) != 0) {
        freopen((s+".in").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

template<typename T, typename V>
bool ckmin(T &a, V b) {return (b < a)? a = b, true : false;}
template<typename T, typename V>
bool ckmax(T &a, V b) {return (b > a)? a = b, true : false;}

void print(int x) {cout << x;}
void print(long long x) {cout << x;}
void print(unsigned x) {cout << x;}
void print(unsigned long long x) {cout << x;}
void print(double x) {cout << fixed << x;}
void print(long double x) {cout << fixed << x;}
void print(char x) {cout << "'" << x << "'";}
void print(string x) {cout << '"' << x << '"';}
void print(bool x) {cout << (x ? "true" : "false");}

template<typename T, typename V>
void print(const pair<T, V> &x) {cout << '{'; print(x.ff); cout << ", "; print(x.ss); cout << '}';}
template<typename T>
void print(const T &x) {int f = 0; cout << '{'; for (auto &i: x) cout << (f++ ? ", " : ""), print(i); cout << "}";}
void _print() {cout << "]" << endl;}
template <typename T, typename... V>
void _print(T t, V... v) {print(t); if (sizeof...(v)) cout << ", "; _print(v...);}

#ifdef TAP
#define bug(x...) cout << "[" << #x << "] = ["; _print(x)
#else
#define bug(x...) 
#endif

const int maxN = 200008;
int low[maxN], num[maxN], bvcccnt = 1, N, cnt, n, sz[maxN];
vt<int> bvccs_ke[maxN], ke[maxN];
stack<int> s;
ll ans;

void dfs1(int u, int p = 0) {
    low[u] = num[u] = ++cnt;
    s.push(u);
    ++N;
    trav(v, ke[u]) {
        if (v == p) continue;
        if (num[v] == 0) {
            dfs1(v, u);
            ckmin(low[u], low[v]);
            if (low[v] >= num[u]) {
                bug(u, v);
                bvccs_ke[u].pb(n+bvcccnt);
                while(s.top() != v) {
                    bvccs_ke[n+bvcccnt].pb(s.top());
                    s.pop();
                }
                bvccs_ke[n+bvcccnt].pb(s.top());
                s.pop();
                bug(bvccs_ke[n+bvcccnt]);
                ++bvcccnt;
            }
        } else ckmin(low[u], num[v]);
    }
}

void dfs2(int u) {
    sz[u] = (u <= n);
    trav(v, bvccs_ke[u]) {
        dfs2(v);
        sz[u] += sz[v];
        if (u > n) ans -= sz(bvccs_ke[u])*sz[v]*(sz[v]-1);
       // bug(u, bvccs_ke[u]);
    //   bug(sz[v]);
    //   bug(ans);
    }
    if (u > n) ans -= sz(bvccs_ke[u])*(N-sz[u])*(N-sz[u]-1);
   // bug(u, bvccs_ke[u]);
   // bug(sz[u]);
 //   bug(ans);
}

int main() {
    #ifndef TAP 
    setIO("");
    //setIOusaco("duatholon2018");
    #endif

    fast;
    int m;
    cin >> n >> m;
    fto(i, 1, m){
        int u, v;
        cin >> u >> v;
        ke[u].pb(v);
        ke[v].pb(u);
    }

    fto(i, 1, n) {
        if (num[i] == 0) {
            N = 0;
            dfs1(i);
            ans += N*(N-1)*(N-2);
            dfs2(i);
        }
    }

    cout << ans << '\n';

    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void setIO(std::string)':
count_triplets.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen((s+".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'void setIOusaco(std::string)':
count_triplets.cpp:51:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |         freopen((s+".in").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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