Submission #1026919

#	Time	Username	Problem	Language	Result	Execution time	Memory
1026919		12345678	Love Polygon (BOI18_polygon)	C++17	29 / 100	228 ms	27220 KiB

polygon

#include <bits/stdc++.h>

using namespace std;

const int nx=1e5+5;

int n, t, vs[nx], l[nx], res, cnt, lv[nx], used[nx];
string su[nx], sv[nx];
map<string, int> mp;
vector<int> d[nx];

void dfs(int u, int p)
{
    for (auto v:d[u]) if (v!=p) dfs(v, u);
    if (u!=p&&!used[u]&&!used[p]) res--, used[u]=used[p]=1; 
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n;
    res=n;
    for (int i=1; i<=n; i++) cin>>su[i]>>sv[i], mp[su[i]]=mp[sv[i]]=0;
    if (n%2) return cout<<-1, 0;
    for (auto &[x, y]:mp) y=++t;
    for (int i=1; i<=n; i++) if (mp[su[i]]!=mp[sv[i]]) lv[mp[su[i]]]=1, d[mp[sv[i]]].push_back(mp[su[i]]);
    for (int i=1; i<=n; i++) if (!lv[i]) dfs(i, i);
    cout<<res;
}

• Subtask 1: 0 / 21
• Subtask 2: 0 / 25
• Subtask 3: 29 / 29
• Subtask 4: 0 / 25