Submission #1122071

#	Time	Username	Problem	Language	Result	Execution time	Memory
1122071		vjudge1	Stranded Far From Home (BOI22_island)	C++17	35 / 100	304 ms	76176 KiB

island

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <cassert>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <fstream>
#include <unordered_map>
using namespace std;
#define ll long long
#define ff first
#define ss second
#define pb push_back 
#define pf push_front
#define UseOFF ios_base::sync_with_stdio(0);cin.tie(0), cout.tie(0);
#define sz size
#define ins insert
#define new junkedseduneon
#define prev usfdjik
const ll N = 2e6 + 111;
ll a[N];
vector <ll> v[N];
bool used[N];
bool used2[N];
ll sum[N];
ll r[N];
bool ans[N];
void dfs(ll x, ll p) {
    used[x] = 1;
    sum[x] += sum[p];
    if(p != 0) sum[x] += a[x];
    // if(x == ) {
    //     cout << sum[x] << " " << sum[p] << " " << p << '\n';
    // }
    for(auto to : v[x]) {
        if(to > x || v[to].sz() > 2) {
            continue;
        }
        dfs(to, x);
    }
}
void dfs2(ll x, ll p) {
    used[x] = 1;
    sum[x] = a[x] + sum[p];
    for(auto to : v[x]) {
        if(used[to]) continue;
        if(to > x) {
            return;
        }
        dfs(to, x);
    }
}
pair <ll, ll> t[N + N + N + N];
void build(ll v, ll tl, ll tr) {
    if(tl == tr) {
        t[v].ff = a[tl];
        t[v].ss = tl;
        return;
    }
    ll L = v + v, R = v + v + 1, tm = (tl + tr) / 2;
    build(L, tl, tm);
    build(R, tm + 1, tr);
    t[v].ff = max(t[L].ff, t[R].ff);
    if(t[L].ff > t[R].ff) {
        t[v].ss = t[L].ss;
    }
    else t[v].ss = t[R].ss;
}
ll mx = 0, pos = 0;
void get(ll v, ll tl, ll tr, ll l, ll r) {
    if(l > tr || r < tl) return;
    if(l <= tl && tr <= r) {
        mx = max(mx, t[v].ff);
        if(t[v].ff == mx) pos = t[v].ss;
        return;
    }
    ll L = v + v, R = v + v + 1, tm = (tl + tr) / 2;
    get(L, tl, tm, l, r);
    get(R, tm + 1, tr, l, r);
}
ll p[N];
ll n;
void f(ll l, ll r) {
    //cout << l << " " << r << " " << mx << " "<< pos << '\n';
    if(l > r) return;
    if(l == r) {
        ans[l] = 1;
        return;
    }
    mx = 0;
    get(1, 1, n, l, r);
    ans[pos] = 1;
    if(p[pos - 1] - p[l - 1] >= mx) {
        f(l, pos - 1);
    }
    if(p[r] - p[pos] >= mx) {
        f(pos + 1, r);
    }
}
void solve() {
    ll m;
	cin >> n >> m;
	for(int i = 1; i <= n; i++) {
		cin >> a[i];
		p[i] = p[i - 1] + a[i];
	}
	bool subtask3 = 1;
	for(int i = 1; i <= m; i++) {
		ll x, y;
		cin >> x >> y;
		if(abs(x - y) > 1) subtask3 = 0;
		if(x < y) swap(x, y);
		v[x].pb(y);
		v[y].pb(x);
	}
	if(subtask3 == 1) {
	    build(1, 1, n);
	    f(1, n);	    
	    for(int i = 1; i <= n; i++) cout << ans[i];
	    return;
	}
	if(n <= 2000 && m <= 2000) {
    	for(int i = 1; i <= n; i++) {
    		multiset < pair <ll, ll> > st;
    		st.ins({a[i], i});
    		//cout << x.ff << " " << x.ss << '\n';
    		ll cur = 0;
    		bool bb = 0;
    		for(int j = 1; j <= n; j++) used[j] = 0;
    		used[i] = 1;
    		while(st.sz() > 0) {
    		    vector <ll> g;
    			pair <ll, ll> x = *st.begin();
    			if(cur < x.ff && x.ss != i) {
    			    cout << '0';
    			    bb = 1;
    			    break;
    			}
    			cur += x.ff;
    			for(auto to : v[x.ss]) {
    			    if(used[to]) continue;
    			    //cout << i << " " << cur << " " << to << " " << x.ss << endl;
    				st.ins({a[to], to});
    				used[to] = 1;
    			}
    			st.erase(x);
    		}
    		if(st.sz() == 0) {
    		    cout << '1';
    		}
	    }
	    return;
	}
	for(int i = n; i >= 1; i--) {
	    if(sum[i] == 0) {
	        sum[i] = a[i];
	        for(auto to : v[i]) {
	            if(to > i) sum[i] += sum[to];
	           // if(i == 4) {
	           //     cout << i << " " << to << " " << sum[to] << " " << sum[i] << '\n';
	           // }
	        }
	        dfs(i, 0);
	    }
	    //cout << sum[i] << " " << i << " || ";
	}
	ans[1] = 1;
	for(int i = 2; i <= n; i++) {
	    for(auto to : v[i]) {
	        if(to > i) continue;
	        if(ans[to] == 1) {
	            if(sum[i] >= a[to]) {
	                ans[i] = 1;
	            }
	        }
	    }
	}
	for(int i = 1; i <= n; i++) {
	    cout << ans[i];
	}
}
signed main()
{
	UseOFF
    ll ttt = 1;
    //cin >> ttt;
    while(ttt--)
    {
        solve();
    }
}

Compilation message (stderr)

island.cpp: In function 'void solve()':
island.cpp:146:12: warning: variable 'bb' set but not used [-Wunused-but-set-variable]
  146 |       bool bb = 0;
      |            ^~

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