Submission #944594

#	Time	Username	Problem	Language	Result	Execution time	Memory
944594		yeediot	Mergers (JOI19_mergers)	C++14	100 / 100	931 ms	194204 KiB

mergers

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef local
void setio(){freopen("/Users/iantsai/Library/Mobile Documents/com~apple~CloudDocs/cpp/Empty.md","r",stdin);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
struct line{
    int a,b;
    int operator()(const int x)const{
        return a*x+b;
    }
};
bool check(line l1,line l2,line l3){
    return (l3.b-l2.b)*(l1.a-l2.a)<=(l2.b-l1.b)*(l2.a-l3.a);
}
const int mxn=5e5+5;
vector<int>adj[mxn];
int c[mxn];
int cnt[mxn];
map<int,int>mp[mxn];
bool cut[mxn];
int sum[mxn];
int sm;
void dfs(int v,int pa=-1){
    mp[v][c[v]]++;
    if(mp[v][c[v]]==cnt[c[v]])mp[v].erase(mp[v].find(c[v]));
    for(auto u:adj[v]){
        if(u==pa)continue;
        dfs(u,v);
        if(sz(mp[v])<sz(mp[u]))swap(mp[u],mp[v]);
        for(auto it:mp[u]){
            mp[v][it.F]+=it.S;
            if(mp[v][it.F]==cnt[it.F]){
                mp[v].erase(mp[v].find(it.F));
            }
        }
    }
    if(!sz(mp[v]) and pa!=-1){
        cut[v]=cut[pa]=1;
    }
}
int ans=0;
void calc(int v,int pa){
    int cc=0;
    if(cut[v])sum[v]++;
    for(auto u:adj[v]){
        if(u==pa)continue;
        calc(u,v);
        sum[v]+=sum[u];
        if(sum[u])cc++;
    }
    if(sm-sum[v])cc++;
    if(cc==1 and cut[v])ans++;
}
signed main(){
    setio();
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int n,k;
    cin>>n>>k;
    for(int i=1;i<n;i++){
        int a,b;
        cin>>a>>b;
        adj[a].pb(b);
        adj[b].pb(a);
    }
    for(int i=1;i<=n;i++){
        cin>>c[i];
        cnt[c[i]]++;
    }
    dfs(1,-1);
    for(int i=1;i<=n;i++){
        sm+=cut[i];
    }
    calc(1,-1);
    cout<<(ans+1)/2<<'\n';
}
 /*
 input:
 
 */















 

Compilation message (stderr)

mergers.cpp: In function 'void setIO(std::string)':
mergers.cpp:42:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mergers.cpp:43:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 24 / 24
• Subtask 3: 14 / 14
• Subtask 4: 22 / 22
• Subtask 5: 30 / 30