oj.uz

Submission #118164

# Submission time Handle Problem Language Result Execution time Memory
118164 2019-06-18T09:38:34 Z baluteshih Islands (IOI08_islands) C++14
90 / 100
 1190 ms 131072 KB 
#include <bits/stdc++.h>
#define jizz ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define pb push_back
#define ET cout << "\n"
#define MEM(i,j) memset(i,j,sizeof i)
#define F first
#define S second
#define MP make_pair
#define ALL(v) v.begin(),v.end()
#define DB(a,s,e) {for(int i=s;i<e;++i) cout << a[i] << " ";ET;}
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
vector<int> G[1000005];
deque<int> dq;
bitset<1000005> yc,vis;
ll M,tp,sum[1000005];
pii edge[1000005];
pll cir[1000005];
const ll INF=1e18;
 
bool dfs(int u,int f)
{
	int flag=0;
	vis[u]=1;
	for(int i:G[u])
		if(i!=f)
			if(!vis[i])
				if(dfs(i,i))
					flag=1,cir[tp-1].S=edge[i].S;
				else;
			else if(!yc[u])
				flag=1,yc[i]=1,cir[tp++]=MP(i,edge[i].S);
	if(u!=f)
		if(!vis[edge[u].F])
			if(dfs(edge[u].F,u))
				flag=1,cir[tp-1].S=edge[u].S;
			else;
		else if(!yc[u])
			flag=1,yc[edge[u].F]=1,cir[tp++]=MP(edge[u].F,edge[u].S);
	if(flag)
		if(yc[u]) flag=0;
		else cir[tp++]=MP(u,0),yc[u]=1;
	return flag;
}
 
ll dfs2(int u)
{
	ll mx=0,sx=0;
	yc[u]=1;
	for(int i:G[u])
		if(!yc[i])
		{
			ll d=dfs2(i)+edge[i].S;
			if(d>mx) sx=mx,mx=d;
			else if(d>sx) sx=d;
		}
	if(!yc[edge[u].F])
	{
		ll d=dfs2(edge[u].F)+edge[u].S;
		if(d>mx) sx=mx,mx=d;
		else if(d>sx) sx=d;
	}
	M=max(M,sx+mx);
	vector<int>().swap(G[u]);
	return mx;
}
 
int main()
{
	int n;
	ll ans=0;
	scanf("%d",&n);
	for(int i=1;i<=n;++i)
	{
		scanf("%d%d",&edge[i].F,&edge[i].S);
		if(edge[i].F!=i) G[edge[i].F].pb(i);
	}
	for(int i=1;i<=n;++i)
		if(!vis[i])
		{
			tp=0,M=0,dfs(i,-1);
			deque<int>().swap(dq);
			for(int j=0;j<tp;++j)
				cir[j].F=dfs2(cir[j].F);
			if(tp>1)
			{
				sum[0]=0,dq.pb(0);
				for(int j=1;j<2*tp;++j)
				{
					while(dq.size()&&j-dq[0]>=tp) dq.pop_front();
					sum[j%tp]=sum[(j-1)%tp]+cir[(j-1)%tp].S,M=max(M,sum[j%tp]+cir[j%tp].F+cir[dq[0]%tp].F-sum[dq[0]%tp]);
					while(dq.size()&&cir[j%tp].F-sum[j%tp]>=cir[dq.back()%tp].F-sum[dq.back()%tp])
						dq.pop_back();
					dq.pb(j);
				}
			}
			ans+=M;
		}
	printf("%lld\n",ans);
}

Compilation message

islands.cpp: In function 'bool dfs(int, int)':
islands.cpp:29:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   if(i!=f)
     ^
islands.cpp:36:4: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
  if(u!=f)
    ^
islands.cpp:43:4: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
  if(flag)
    ^
islands.cpp: In function 'int main()':
islands.cpp:75:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
islands.cpp:78:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&edge[i].F,&edge[i].S);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23808 KB Output is correct
2 Correct 22 ms 23808 KB Output is correct
3 Correct 23 ms 23936 KB Output is correct
4 Correct 21 ms 23876 KB Output is correct
5 Correct 23 ms 23808 KB Output is correct
6 Correct 22 ms 23808 KB Output is correct
7 Correct 21 ms 23808 KB Output is correct
8 Correct 22 ms 23800 KB Output is correct
9 Correct 24 ms 23808 KB Output is correct
10 Correct 22 ms 23808 KB Output is correct
11 Correct 23 ms 23800 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23980 KB Output is correct
2 Correct 21 ms 23936 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 23936 KB Output is correct
2 Correct 24 ms 24196 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 24448 KB Output is correct
2 Correct 39 ms 26360 KB Output is correct
3 Correct 31 ms 24440 KB Output is correct
4 Correct 26 ms 24056 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 47 ms 27388 KB Output is correct
2 Correct 62 ms 28792 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 96 ms 31224 KB Output is correct
2 Correct 127 ms 41204 KB Output is correct
3 Correct 144 ms 48220 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 180 ms 37396 KB Output is correct
2 Correct 242 ms 59180 KB Output is correct
3 Correct 323 ms 77488 KB Output is correct
4 Correct 335 ms 86904 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 282 ms 35876 KB Output is correct
2 Correct 972 ms 106644 KB Output is correct
3 Correct 334 ms 46876 KB Output is correct
4 Correct 466 ms 85120 KB Output is correct
5 Correct 453 ms 82808 KB Output is correct
6 Correct 1190 ms 51116 KB Output is correct
7 Correct 506 ms 131072 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 384 ms 131072 KB Execution killed with signal 9 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -