Submission #1104956

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104956		koukirocks	Stranded Far From Home (BOI22_island)	C++17	100 / 100	162 ms	28600 KiB

island

#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx,avx2")
//#pragma GCC target("popcnt")
 
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
const ll MAX=2e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
const ldb eps=1e-6;
const ldb PI=acos(-1.0);
const int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
template<typename T>
using vvector = vector<vector<T>>;

struct DSU {
    int n;
    vector<ll> fa;
    vector<ll> cnt;
    vector<ll> del;
    DSU(int _n,vector<pll> &w):n(_n) {
        fa.resize(n+1);
        cnt.resize(n+1);
        del.resize(n+1);
        for (int i=0;i<n;i++) {
            cnt[w[i].S]=w[i].F;
        }
        iota(all(fa),0);
    }
    pll get(ll x) {
        if (fa[x]==x) return {del[x],x};
        else {
            pll ret = get(fa[x]);
            del[x]|=ret.F;
            fa[x]=ret.S;
            return {del[x]|ret.F,ret.S};
        }
    }
    void unionn(int a,int b) {
        a=get(a).S;b=get(b).S;
        if (a==b) return;
        fa[a]=b;
        cnt[b]+=cnt[a];
    }
};

int main() {
    speed;
    int n,m;
    cin>>n>>m;
    vvector<ll> G(n+1);
    vector<pll> w;
    vector<ll> cnt(n+1);
    for (int i=1;i<=n;i++) {
        cin>>cnt[i];
        w.emplace_back(cnt[i],i);
    }
    sort(all(w));
    for (int i=0;i<m;i++) {
        ll a,b;
        cin>>a>>b;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    DSU d(n,w);
    for (int i=1;i<n;i++) {
        ll v=w[i].S;
        for (ll u:G[v]) {
            if (cnt[u]>cnt[v]) continue;
            ll ru=d.get(u).S;
            if (d.cnt[ru]<cnt[v]) d.del[ru]=true;
            d.unionn(u,v);
        }
    }
    for (int i=1;i<=n;i++) {
        pll ret = d.get(i);
        cout<<!(d.del[i]);
    }
    return 0;
}

Compilation message (stderr)

island.cpp: In function 'int main()':
island.cpp:86:13: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
   86 |         pll ret = d.get(i);
      |             ^~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 30 / 30
• Subtask 5: 35 / 35