Submission #369928

#	Time	Username	Problem	Language	Result	Execution time	Memory
369928		arnold518	Fish (IOI08_fish)	C++14	100 / 100	616 ms	22508 KiB

fish

#include <bits/stdc++.h>
using namespace std;

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

const int MAXN = 5e5;
const int SEGN = 524288;

int N, K;
ll MOD;
pii B[MAXN+10];
int C[MAXN+10];

int cnt[MAXN+10];
pii P[MAXN+10];
int I[MAXN+10];

ll ans;

struct SEG
{
	ll tree[SEGN*2+10];
	void init()
	{
		for(int i=0; i<SEGN*2+10; i++) tree[i]=1;
	}
	void update(int p)
	{
		p+=SEGN;
		tree[p]++; tree[p]%=MOD;
		for(int node=p>>1; node; node>>=1) tree[node]=tree[node<<1]*tree[node<<1|1]%MOD;
	}
	ll query(int l, int r)
	{
		ll ret=1;
		r++;
		for(l+=SEGN, r+=SEGN; l<r; l>>=1, r>>=1)
		{
			if(l&1) ret=ret*tree[l++]%MOD;
			if(r&1) ret=ret*tree[--r]%MOD;
		}
		return ret;
	}
}seg;

int V[MAXN+10];

int main()
{
	scanf("%d%d%lld", &N, &K, &MOD);
	for(int i=1; i<=N; i++) scanf("%d%d", &B[i].first, &B[i].second);

	sort(B+1, B+N+1);
	
	for(int i=1; i<=K; i++) P[i].second=i;
	for(int i=1; i<=N; i++)
	{
		P[B[i].second].first=B[i].first;
	}

	sort(P+1, P+K+1);

	for(int i=1; i<=K; i++) I[P[i].second]=i;
	for(int i=1; i<=N; i++) B[i].second=I[B[i].second];
	for(int i=1; i<=N; i++) C[B[i].second]=i;

	seg.init();
	for(int i=1; i<=K; i++) V[i]=K+1;
	for(int i=1, j=1; i<=N; i++)
	{
		if(C[B[i].second]!=i) continue;
		for(; j<=N && B[j].first*2<=B[i].first; j++)
		{
			seg.update(B[j].second);
			if(B[j].second<B[i].second && V[B[j].second]==K+1) V[B[j].second]=B[i].second;
		}
		ans+=seg.query(1, B[i].second);
		ans%=MOD;
	}

	seg.init();
	for(int i=1, j=1; i<=N; i++)
	{
		if(C[B[i].second]!=i) continue;
		for(; j<=N && B[j].first*2<=B[i].first; j++)
		{
			seg.update(B[j].second);
		}
		if(B[i].second+1<=V[B[i].second]-1)
		{
			ll t=(seg.query(B[i].second+1, V[B[i].second]-1)+MOD-1)%MOD;
			t*=seg.query(1, B[i].second-1); t%=MOD;
			ans+=t; ans%=MOD;
		}
	}

	printf("%lld\n", ans);
}

Compilation message (stderr)

fish.cpp: In function 'int main()':
fish.cpp:52:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   52 |  scanf("%d%d%lld", &N, &K, &MOD);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
fish.cpp:53:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   53 |  for(int i=1; i<=N; i++) scanf("%d%d", &B[i].first, &B[i].second);
      |                          ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
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