Submission #1118722

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118722		vjudge	Duathlon (APIO18_duathlon)	C++17	100 / 100	162 ms	55272 KiB

count_triplets

#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define F first
#define S second
#define ALL(x) x.begin(),x.end()
#define random(l, r) (l + rand() % (r - l + 1))
#define int long long
#define maxn 500005
#define bit(x, i) ((x >> i) & 1)
#define pii pair<int, int>
#define MOD 1000000007
#define Task "BIKERACE"
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>ordered_set;
int n,m,low[maxn],id[maxn],dem = 0,cnt,num = 0,scc[maxn];
vector<int>adj[maxn],luu[maxn];
ordered_set st[10105];
void Add(int &a,int b)
{
    a += b;
    if(a >= MOD)a -= MOD;
    if(a < 0)a += MOD;
}
stack<int>s;
void DFS(int u)
{
    low[u] = id[u] = ++dem;
    s.push(u);
	++num;
	for (int v : adj[u]) {
		if (!id[v]) {
			DFS(v);
			low[u] = min(low[u], low[v]);
			if (low[v] == id[u]) {
				scc[++cnt] = 0;
				while(1){
					int x = s.top();
                    s.pop();
					luu[cnt].push_back(x);
                    luu[x].push_back(cnt);
					++scc[cnt];
					if(x == v)break;
				}
				luu[cnt].push_back(u);
				luu[u].push_back(cnt);
				++scc[cnt];

			}
		} else low[u] = min(low[u], id[v]);
	}
}

int sz[maxn],ans = 0;
void Tinh(int u, int par) {
	sz[u] = (u <= n);
	for (int v : luu[u]){
        if (v == par)continue;
        Tinh(v,u);
        ans += 2ll * scc[u] * sz[u] * sz[v];
        sz[u] += sz[v];
	}
	ans += 2ll * scc[u] * sz[u] * (num - sz[u]);
}
signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if(fopen(Task".inp", "r"))
    {
        freopen(Task".inp", "r", stdin);
        freopen(Task".out", "w", stdout);
    }
    cin >> n >> m;
    for(int i = 1; i <= n; i++) scc[i] = -1;
    for(int i = 1; i <= m; i++)
    {
        int u,v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    cnt = n;
    for(int i = 1; i <= n; i++){
        if(id[i])continue;
        num = 0;
        DFS(i);
        Tinh(i,0);
    }
    cout << ans;
}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen(Task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:74:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         freopen(Task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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