oj.uz

Submission #198789

# Submission time Handle Problem Language Result Execution time Memory
198789 2020-01-27T17:02:39 Z arnold518 Islands (IOI08_islands) C++14
64 / 100
 2000 ms 131072 KB 
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 1e6;

int N;
vector<pll> adj[MAXN+10];
pll to[MAXN+10];
ll ans;

bool vis[MAXN+10], chk[MAXN+10];

ll dfs(int now, ll dep)
{
	vis[now]=true;
	ll ret=dep;
	for(auto nxt : adj[now])
	{
		if(vis[nxt.first]) continue;
		ret=max(ret, dfs(nxt.first, dep+nxt.second));
	}
	return ret;
}

int main()
{
	int i, j;

	scanf("%d", &N);
	for(i=1; i<=N; i++)
	{
		int u=i, v, w;
		scanf("%d%d", &v, &w);
		to[u]={v, w};
		adj[v].push_back({u, w});
	}

	for(i=1; i<=N; i++)
	{
		if(vis[i]) continue;

		int now=i;
		vector<int> cyc;
		while(!chk[now])
		{
			cyc.push_back(now);
			chk[now]=1;
			now=to[now].first;
		}

		reverse(cyc.begin(), cyc.end());
		while(!cyc.empty() && cyc.back()!=now) cyc.pop_back();
		reverse(cyc.begin(), cyc.end());

		//for(auto it : cyc) printf("%d ", it); printf("\n");

		vector<ll> A, D;
		ll val=0, s=0;

		D.push_back(0);
		for(auto it : cyc) vis[it]=1;
		for(auto it : cyc) A.push_back(dfs(it, 0));
		for(auto it : cyc) D.push_back(D.back()+to[it].second), s+=to[it].second;
		D.pop_back();

		for(auto it : A) val=max(val, it);

		ll t=-1e18;
		for(i=0; i<cyc.size(); i++)
		{
			if(i) val=max(val, D[i]+A[i]+t);
			t=max(t, A[i]-D[i]);
		}

		t=-1e18;
		for(i=0; i<cyc.size(); i++)
		{
			if(i) val=max(val, s-D[i]+A[i]+t);
			t=max(t, D[i]+A[i]);
		}

		ans+=val;
	}
	printf("%lld", ans);
}

Compilation message

islands.cpp: In function 'int main()':
islands.cpp:73:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(i=0; i<cyc.size(); i++)
            ~^~~~~~~~~~~
islands.cpp:80:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(i=0; i<cyc.size(); i++)
            ~^~~~~~~~~~~
islands.cpp:31:9: warning: unused variable 'j' [-Wunused-variable]
  int i, j;
         ^
islands.cpp:33:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
islands.cpp:37:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &v, &w);
   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
27.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 23800 KB Output is correct
2 Incorrect 20 ms 23800 KB Output isn't correct
3 Correct 19 ms 23800 KB Output is correct
4 Correct 19 ms 23744 KB Output is correct
5 Correct 20 ms 23800 KB Output is correct
6 Correct 19 ms 23800 KB Output is correct
7 Correct 19 ms 23800 KB Output is correct
8 Correct 19 ms 23800 KB Output is correct
9 Correct 20 ms 23804 KB Output is correct
10 Incorrect 20 ms 23800 KB Output isn't correct
11 Correct 19 ms 23800 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 23928 KB Output is correct
2 Correct 20 ms 23932 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 23928 KB Output is correct
2 Correct 22 ms 24056 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 24696 KB Output is correct
2 Correct 37 ms 26232 KB Output is correct
3 Correct 30 ms 25148 KB Output is correct
4 Incorrect 25 ms 24440 KB Output isn't correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 45 ms 27252 KB Output is correct
2 Correct 63 ms 30136 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 109 ms 35700 KB Output is correct
2 Correct 107 ms 39544 KB Output is correct
3 Correct 133 ms 43112 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 184 ms 47292 KB Output is correct
2 Correct 211 ms 56144 KB Output is correct
3 Correct 228 ms 65608 KB Output is correct
4 Correct 302 ms 71388 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 348 ms 71812 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2062 ms 131072 KB Time limit exceeded
2 Halted 0 ms 0 KB -