Submission #537756

#	Time	Username	Problem	Language	Result	Execution time	Memory
537756		kabika	Walking (NOI12_walking)	C++17	0 / 25	1 ms	212 KiB

walking

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ti w[i].first
#define vi w[i].second
#define tj w[j].first
#define vj w[j].second

struct UFDS
{
    vector<int> root, sz;
    UFDS(int n) : root(n), sz(n, 1)
    {
        iota(root.begin(), root.end(), 0);
    }
    int findRoot(int x)
    {
        return x == root[x] ? x : root[x] = findRoot(root[x]);
    }
    bool same(int x, int y)
    {
        return findRoot(x) == findRoot(y);
    }
    bool unite(int x, int y)
    {
        x = findRoot(x);
        y = findRoot(y);
        if(x == y)
            return 0;
        if(sz[x] < sz[y])
            swap(x, y);
        sz[x] += sz[y];
        root[y] = x;
        return 1;
    }
    int size(int x)
    {
        return sz[findRoot(x)];
    }
};

int main() 
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int l, n;
	cin >> l >> n;
	vector<pair<int,int>> w(n);
	for(int i = 0; i < n; ++i)
	    cin >> ti >> vi;
	sort(w.begin(), w.end());
	    
	UFDS ds(n);
	for(int i = 0; i < n; ++i)
	{
	    for(int j = i + 1; j < n; ++j)
	    {
	        if(!ds.same(i,j))
	        {
	            double m1 = (double)l/vi + ti;
	            double m2 = (double)l/vj + tj;
	            if(vi != vj && m2 > m1)
	                ds.unite(i, j);
	        }
	    }
	}
	
	int frsz = 0;
	for(int i = 0; i < n; ++i)
	    frsz = max(frsz, ds.size(i));
	    
	cout << frsz << '\n';
	return 0;
}

• Subtask 1: 0 / 3
• Subtask 2: 0 / 3
• Subtask 3: 0 / 5
• Subtask 4: 0 / 7
• Subtask 5: 0 / 7