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Submission #440024

# Submission time Handle Problem Language Result Execution time Memory
440024 2021-07-01T12:49:52 Z dutch Islands (IOI08_islands) C++17
80 / 100
 718 ms 131076 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define sub(u) d(t[u], t[u] + s[u] - 1)
#define dis(u) d(t[u], t[u])
#define w (a[e][1])
#define v() (e == u ? a[e][0] : e)
 
const int LIM = 1e6;
 
template<class T> struct SegmentTree{
	int n = LIM, i; T a[2*LIM] ;
	SegmentTree& operator[](int j){ i=j+n; return *this; }
	void operator=(T v){
		for(a[i]=v; i/=2; ) a[i] = max(a[2*i], a[2*i+1]); }
	T operator()(int l, int r){
		T x = 0;
		for(l+=n, r+=n+1; l<r; l/=2, r/=2){
			if(l & 1) x = max(x, a[l++]);
			if(r & 1) x = max(x, a[--r]);
		}
		return x;
	}
};
 
vector<int> g[LIM];
array<int, 2> a[LIM];
int r, p[LIM], dfsTimer, t[LIM], s[LIM];
ll best, lastDist;
bitset<LIM> vis;
SegmentTree<ll> d;
 
void dfs(int u){
	s[u] = 1;
	ll curr = 0;
	t[u] = dfsTimer++;
	d[t[u]] = (u == r ? 0LL : lastDist);
	for(int e : g[u]) if(e != r && !s[v()]){
		lastDist = dis(u) + (ll)w, p[v()] = u;
		dfs(v());
		s[u] += s[v()];
		best = max(best, curr + sub(v()) - dis(u));
		curr = max(curr, sub(v()) - dis(u));
	}
}
 
void findCycle(int u, int par){
	vis[u] = 1;
	for(int e : g[u]) if(e != par){
		if(vis[v()]) return void(r = e);
		findCycle(v(), e);
		if(r >= 0) return;
	}
	vis[u] = 0;
}
 
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n; cin >> n;
 
	for(int i=0; i<n; ++i){
		cin >> a[i][0] >> a[i][1]; --a[i][0];
		g[a[i][0]].push_back(i);
		g[i].push_back(i);
	}
	fill(p, p+n, -1);
 
	ll ans = 0;
 
	for(int z=0; z<n; ++z){
		if(s[z]) continue;
		r = -1, best = 0;
		findCycle(z, -1);
		bool cycle = r >= 0;
		if(!cycle) r = z;
 
		dfsTimer = 0;
		dfs(r);
 
		if(!cycle){
			ans += best;
			continue;
		}
		assert(cycle);
 
		int u = a[r][0], last = -1;
		ll res = 0, ex;
		while(u != r){
			ll mx = 0;
			for(int e : g[u])
				if(e != r && v() != p[u] && v() != last) mx = max(mx, sub(v()) - dis(u));
 
			ex = max(d(0, t[u]-1), d(t[u]+s[u], dfsTimer-1));
			res = max(res, dis(a[r][0]) - dis(u) + mx + ex);
			last = u;
			u = p[u];
		}
		res += a[r][1];
 
		ans += max(best, res);
		for(int i=0; i<dfsTimer; ++i) d[i] = 0;
	}
 
	cout << ans;
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 23884 KB Output is correct
2 Correct 14 ms 23884 KB Output is correct
3 Correct 15 ms 23968 KB Output is correct
4 Correct 14 ms 23828 KB Output is correct
5 Correct 16 ms 23884 KB Output is correct
6 Correct 15 ms 23884 KB Output is correct
7 Correct 14 ms 23884 KB Output is correct
8 Correct 15 ms 23892 KB Output is correct
9 Correct 16 ms 23844 KB Output is correct
10 Correct 16 ms 23884 KB Output is correct
11 Correct 15 ms 23884 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23972 KB Output is correct
2 Correct 15 ms 23884 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23884 KB Output is correct
2 Correct 17 ms 24268 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 24900 KB Output is correct
2 Correct 45 ms 27764 KB Output is correct
3 Correct 30 ms 25208 KB Output is correct
4 Correct 22 ms 24492 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 63 ms 29292 KB Output is correct
2 Correct 77 ms 31220 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 163 ms 39456 KB Output is correct
2 Correct 219 ms 45628 KB Output is correct
3 Correct 243 ms 56980 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 285 ms 46400 KB Output is correct
2 Correct 398 ms 79292 KB Output is correct
3 Correct 496 ms 87748 KB Output is correct
4 Correct 532 ms 108900 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 545 ms 94312 KB Output is correct
2 Runtime error 718 ms 131076 KB Execution killed with signal 9
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 399 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -