oj.uz

Submission #216537

# Submission time Handle Problem Language Result Execution time Memory
216537 2020-03-27T13:13:40 Z songc Islands (IOI08_islands) C++14
90 / 100
 879 ms 131076 KB 
#include <bits/stdc++.h>
#define pb push_back
#define all(v) v.begin(),v.end()
#define fi first
#define se second
#define INF (1ll<<60)
using namespace std;
typedef long long LL;
typedef pair<LL,LL> pii;

int N, M;
LL ans, ret, W[1010101];
int P[1010101], deg[1010101];
bool chk[1010101];
vector<int> adj[1010101];
vector<LL> V, S;

int cyc(int u){
	if (chk[u]) return u;
	chk[u] = true;
	int r = cyc(P[u]);
	if (r){
		V.pb(u), S.pb(W[u]);
		return (r==u)?0:r;
	}
	chk[u] = false;
	return 0;
}

LL dfs(int u){
	LL mx=0;
	chk[u] = true;
	for (int v : adj[u]){
		if (chk[v]) continue;
		LL r = dfs(v) + W[v];
		ret = max(ret, mx+r);
		mx = max(mx, r);
	}
	return mx;
}

void dia(int u){
	V.clear(), S.clear();
	cyc(u);
	reverse(all(V)); reverse(all(S));
	for (LL &v : V) v = dfs(v);
	M = V.size();
	for (int i=M-1; i>0; i--) swap(S[i], S[i-1]);
	for (int i=1; i<M; i++) S[i] += S[i-1];
	LL m1=-INF, m2=-INF;
	for (int i=0; i<M; i++){
		ret = max(ret, m1+S[i]+V[i]);
		ret = max(ret, m2-S[i]+V[i]+S[M-1]);
		m1 = max(m1, V[i]-S[i]);
		m2 = max(m2, V[i]+S[i]);
	}
}

int main(){
	scanf("%d", &N);
	for (int i=1; i<=N; i++){
		scanf("%d %lld", &P[i], &W[i]);
		deg[P[i]]++;
	}
	for (int i=1; i<=N; i++) adj[i].resize(deg[i]);
	for (int i=1; i<=N; i++) adj[P[i]].pb(i);
	for (int i=1; i<=N; i++){
		if (chk[i]) continue;
		dia(i);
		ans+=ret, ret=0;
	}
	printf("%lld\n", ans);
	return 0;
}

Compilation message

islands.cpp: In function 'int main()':
islands.cpp:60:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
islands.cpp:62:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %lld", &P[i], &W[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 24064 KB Output is correct
2 Correct 19 ms 24064 KB Output is correct
3 Correct 19 ms 24064 KB Output is correct
4 Correct 20 ms 24064 KB Output is correct
5 Correct 18 ms 24064 KB Output is correct
6 Correct 23 ms 24064 KB Output is correct
7 Correct 18 ms 24064 KB Output is correct
8 Correct 19 ms 24064 KB Output is correct
9 Correct 18 ms 24064 KB Output is correct
10 Correct 18 ms 24064 KB Output is correct
11 Correct 19 ms 24064 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 24192 KB Output is correct
2 Correct 18 ms 24192 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 24192 KB Output is correct
2 Correct 19 ms 24448 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 25276 KB Output is correct
2 Correct 33 ms 26872 KB Output is correct
3 Correct 28 ms 25212 KB Output is correct
4 Correct 28 ms 24580 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 28148 KB Output is correct
2 Correct 55 ms 30752 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 100 ms 35364 KB Output is correct
2 Correct 106 ms 43084 KB Output is correct
3 Correct 123 ms 49252 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 164 ms 46072 KB Output is correct
2 Correct 209 ms 61900 KB Output is correct
3 Correct 241 ms 78476 KB Output is correct
4 Correct 283 ms 87132 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 338 ms 60188 KB Output is correct
2 Correct 542 ms 110804 KB Output is correct
3 Correct 315 ms 64632 KB Output is correct
4 Correct 397 ms 96480 KB Output is correct
5 Correct 388 ms 93916 KB Output is correct
6 Correct 879 ms 74952 KB Output is correct
7 Correct 472 ms 123704 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 474 ms 131076 KB Execution killed with signal 9 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -