Submission #601215

#	Time	Username	Problem	Language	Result	Execution time	Memory
601215		TimDee	Stranded Far From Home (BOI22_island)	C++17	20 / 100	405 ms	67356 KiB

island

#include <bits/stdc++.h>
using namespace std;
 
#define paiu return
#define moment 0;
 
#define int long long
#define double long double
#define ll long long

#define forr(i,x) for (int i=0; i<x; i++)
#define forn(i,x) for (int i=0; i<x; i++)

#define vi(a,n) vector<int> a(n,0)
 
//cringe define
#define vii(a,n) vi(a,n); forr(i,n) cin>>a[i];
vector<int> ___makeprefsum(vector<int>&a) {
    int n=a.size();
    vi(pr,n+1);
    forn(i,n) pr[i+1]=pr[i]+a[i];
    return pr;
}
#define prefsum(pr,a) vector<int> pr=___makeprefsum(a);
 
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
 
#define pb(x) push_back(x)
#define pf pop_front();
#define last(c) c[c.size()-1]
 
#define f first
#define s second
 
#define pi pair<int, int>
#define mp(x,y) make_pair(x, y)
 
const ll mod = 1000000007;
const double ppi = acos(0) * 2;
     
const int maxn = 1e5+1;
const int inf = INT_MAX;
const ll linf = LLONG_MAX;
const ll mmod = 998244353;

vector<int> a;
vector<vector<int>> adj(2e5);
auto cmp = [](int i, int j) { return a[i]<=a[j]; };

void subtask1(int n, int m) {

    string ans(n,'1');

    forn(i,n) {
        set<int,decltype(cmp)> s(cmp);
        int cnt=a[i];
        bitset<2000> vis; vis.set(i,1); //cout<<i+1<<"->";
        for (auto v:adj[i]) { s.insert(v); vis.set(v,1); }
        while (!s.empty()) {
            auto it=s.begin();
            int u=*it;
            //cout<<u+1<<"->";
            if (a[u]>cnt) {ans[i]='0'; break;}
            cnt+=a[u]; 
            vis.set(u,1);
            s.erase(it);
            for (auto v:adj[u]) if (!vis[v]) { s.insert(v); vis.set(v,1); }
        }
        //cout<<'\n';
    }
    cout<<ans<<'\n';
}

void dfs(vector<vector<int>>&adj, vector<int>&vis, vector<int>&d, int v) {
    if (vis[v]) return;
    vis[v]=1;
    d[v]+=a[v]; //cout<<v<<' '<<d[v]<<' '<<a[v]<<'\n';
    for (auto u:adj[v]) {
        dfs(adj,vis,d,u);
        if (u>v) d[v]+=d[u];
    }
}

void ver(vector<vector<int>>&adj, vector<int>&vis, vector<int>&d, vector<int>&up, int v) {
    if (vis[v]) return;
    vis[v]=1;
    for (auto u:adj[v]) {
        if (u<v) continue;
        if (d[u]>=a[v]) {
            up[u]=1;
            ver(adj,vis,d,up,u);
        }
    }
}

void subtask2(int n, int m) {
    vector<int> up(n,0);
    vector<int> d(n,0), vis(n,0);
    dfs(adj,vis,d,0);
    //forn(i,n) cout<<d[i]<<' '; cout<<'\n';
    up[0]=1;
    vis.assign(n,0);
    ver(adj,vis,d,up,0);
    forn(i,n) cout<<up[i]; cout<<'\n';
}

int n;  // array size
vector<int> t;

int merge(int i, int j) {
    if (a[i]<=a[j]) return i;
    else return j;
}

void build(int _n) {  // build the tree
    a.push_back(linf);
    n=_n;
  for (int i = n - 1; i > 0; --i) t[i] = merge ( t[i<<1] , t[i<<1|1] );
}

void modify(int p, int value) {  // set value at position p
  for (t[p += n] = value; p > 1; p >>= 1) t[p>>1] = merge( t[p] , t[p^1] );
}

void subtask3(int n, int m) {
    string ans(n,'1');
    set<int> left;
    forn(i,n) left.insert(i);
    t.assign(2*2e5,n);
    forn(i,n) t[n+i]=i;
    build(n);
    int unvis=n;
    vector<int> d(n,0), vis(n,0);
    forn(i,n) d[i]=a[i];
    while (unvis) {
        int u=t[1]; --unvis;
        if (u==n) break;
        left.erase(left.find(u));
        vector<int> path = {u};
        auto it1=left.upper_bound(u), it2=left.upper_bound(u);
        d.push_back(linf);
        int l=n,r=n;
        if (it1!=left.begin()) {--it1; 
            l=*it1; 
        }
        if (it2!=left.end()) {
            r=*it2;
        }

        while (l!=n || r!=n) {
            int v;
            if (d[l]<=d[r]) v=l;
            else v=r;
            if (a[u]>a[l] && a[u]>a[r]) break;
            else if (a[u]>a[v]) v = (v==l)?r:l;
            if (v==n) {
                for (auto x:path) { modify(x,n); }
                --unvis;
                break;
            }
            if (d[u]>=a[v]) {
                left.erase(left.find(v));
                if (v<u) {
                    auto it1=left.upper_bound(u);
                    if (it1!=left.begin()) {
                        --it1; 
                        l=*it1; 
                    } else l=n;
                } else {
                    auto it2=left.upper_bound(u);
                    if (it2!=left.end()) {
                        r=*it2;
                    } else r=n;
                }
                --unvis;
            } else {
                for (auto x:path) { ans[x]='0'; modify(x,n); }
                d[v]+=d[u];
                break;
            }
            d[v]+=d[u];
            u=v;
            path.pb(v);
        }

    }
    cout<<ans;
}

void solve() {
    
    int n,m; cin>>n>>m;
    vii(b,n); a=b;
    int _p3=1, _p2=1;
    vector<int> lesscnt(n,0);

    forn(i,m) {
        int u,v; cin>>u>>v;
        --u, --v;
        if (u>v) swap(u,v);
        adj[u].pb(v);
        adj[v].pb(u);
        _p3&=(abs(u-v)==1);
        lesscnt[max(u,v)]++;
    }

    forn(i,n) _p2&=(i==0 || (lesscnt[i]==1));

    if (n<=2000 && m<=2000) {
        subtask1(n,m);
        return;
    } 
    forn(i,n-1) _p2&=(a[i]>=a[i+1]);
    if (_p2) {
        subtask2(n,m);
        return;
    }
    if (_p3) {
        subtask3(n,m);
        return;
    }
}

int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    
    int t=1;
    //cin>>t;
    while(t--) solve();
    
    paiu moment
}

Compilation message (stderr)

island.cpp: In function 'void subtask2(long long int, long long int)':
island.cpp:12:19: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   12 | #define forn(i,x) for (int i=0; i<x; i++)
      |                   ^~~
island.cpp:105:5: note: in expansion of macro 'forn'
  105 |     forn(i,n) cout<<up[i]; cout<<'\n';
      |     ^~~~
island.cpp:105:28: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  105 |     forn(i,n) cout<<up[i]; cout<<'\n';
      |                            ^~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 30
• Subtask 5: 0 / 35