Submission #1102918

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102918		Cadoc	Hotspot (NOI17_hotspot)	C++14	100 / 100	568 ms	5456 KiB

hotspot

/*
    Author: Cadocx
    Codeforces: https://codeforces.com/profile/Kadoc
    VNOJ: oj.vnoi.info/user/Cadoc
*/

#include <bits/stdc++.h>
using namespace std;

// input/output
#define fastIO ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define el cout << '\n'
#define debug(x) cout << #x << " = " << x << '\n'
#define execute cerr << "Time elapsed: " << (1.0 * clock() / CLOCKS_PER_SEC) << "s"
// #pragma GCC optimize("O2", "unroll-loops", "Ofast")
// #pragma GCC target("avx,avx2,fma")
//data type
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define piv pair<int, vector<int>>
#define vi vector<int>
#define vl vector<ll>
#define vc vector<char>
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return 1; }; return 0; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return 1; }; return 0; }
//STL
#define sz(x) (int)(x).size()
#define FOR(i,l,r) for(auto i = l; i <= r; i++)
#define FORD(i,r,l) for(auto i = r; i >= l; i--)
#define forin(i,a) for(auto i : a)
#define pb push_back
#define eb emplace_back
#define pf push_front
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
//bitmask
#define bitcnt(n) __builtin_popcount(n)
#define mask(i) (1 << (i))
#define bit(n, i) (((n) >> (i)) & 1)
#define set_on(n, i) ((n) | mask(i))
#define set_off(n, i) ((n) & ~mask(i))
//constant
#define N 100005
#define MOD 1000230007
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define base 31
#define Kadoc 0

int n, m, q;
int d[2][N];
ll cnt[2][N];
long double f[N];
vector<int> g[N];

void ditcha(int d[], ll cnt[], int s){
	queue<int> q;
	FOR(i, 0, n-1) d[i] = -1, cnt[i] = 0;

	d[s] = 0;
	cnt[s] = 1;
	q.push(s);

	while(q.size()){
		int u = q.front(); q.pop();

		for(int v:g[u]){
			if(d[v] < 0){
				d[v] = d[u] + 1;
				cnt[v] = cnt[u];
				q.push(v);
			}
			else if(d[v] == d[u] + 1) cnt[v] += cnt[u];
		}
	}
}

void solve(){
    cin >> n >> m;
    FOR(i, 1, m){
    	int u, v; cin >> u >> v;
    	g[u].pb(v);
    	g[v].pb(u);
    }

    cin >> q;
    while(q--){
    	int u, v; cin >> u >> v;

    	ditcha(d[0], cnt[0], u);
    	ditcha(d[1], cnt[1], v);

    	FOR(i, 0, n-1) if(d[0][i] + d[1][i] == d[0][v]){
    		ll tot = cnt[0][i] * cnt[1][i];
    		f[i] += (long double) tot / (long double) cnt[0][v];
    	}
    }

    int Ans = -1;
    FOR(i, 0, n-1) if(Ans < 0 || f[Ans] < f[i]) Ans = i;

    cout << Ans;
}

int main(){
    #define NAME "TASK"
    if(fopen(NAME".inp", "r")){
        freopen(NAME".inp", "r", stdin);
        freopen(NAME".out", "w", stdout);
    }

    fastIO;
    
    if(Kadoc){
        int tc; cin >> tc;
        while(tc--){
            solve();
        }
    } else solve();
}

Compilation message (stderr)

hotspot.cpp: In function 'int main()':
hotspot.cpp:111:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  111 |         freopen(NAME".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
hotspot.cpp:112:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  112 |         freopen(NAME".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 18 / 18
• Subtask 5: 26 / 26
• Subtask 6: 36 / 36