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Submission #187532

# Submission time Handle Problem Language Result Execution time Memory
187532 2020-01-13T02:43:29 Z dndhk Watching (JOI13_watching) C++14
50 / 100
 1000 ms 18680 KB 
#include <bits/stdc++.h>

#define pb push_back

using namespace std;

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

const int MAX_N = 2000;
const ll INFLL = 10000;
int N, P, Q;
vector<ll> v;

int dp[MAX_N+1][MAX_N+1];

int lb(ll x){
	//cout<<"?"<<x<<" ";
	int s = 1, e = v.size()-1, m;
	while(s<e){
		m = (s+e)/2+1;
		//cout<<m<<" "<<v[m]<<endl;

		if(v[m]<=x)	s = m;
		else	e = m-1;
	}
	//cout<<s<<endl;
	return s;
}

deque<pii> dq[2][MAX_N+1];

void add(int idx, int x, int y, int z){
	while(!dq[idx][x].empty() && dq[idx][x].back().first>=z){
		dq[idx][x].pop_back();
	}
	dq[idx][x].push_back({z, y});
}

bool chk(ll x){
	for(int i=0; i<=N; i++){
		for(int j=0; j<=N; j++)	dp[i][j] = INFLL;
		while(!dq[0][i].empty())	dq[0][i].pop_back();
		while(!dq[1][i].empty())	dq[1][i].pop_back();
	}
	dp[0][0] = 0LL;
	//cout<<x<<endl;
	int r1=0, r2=0;
	for(int i=0; i<=N; i++){
		while(r1<v.size()-1 && v[r1+1]<=v[i+1]+x-1LL){
			r1++;
		}
		while(r2<v.size()-1 && v[r2+1]<=v[i+1]+2LL*x-1LL){
			r2++;
		}
		for(int j=N; j>=0; j--){
			while(!dq[0][j].empty() && dq[0][j].front().second<i)	dq[0][j].pop_front();
			while(!dq[1][j].empty() && dq[1][j].front().second<i)	dq[1][j].pop_front();
			if(dq[0][j].empty()){
				if(!dq[1][j].empty())	dp[i][j] = dq[1][j].front().first;
			}else{
				if(dq[1][j].empty())	dp[i][j] = dq[0][j].front().first;
				else{
					dp[i][j] = min(dq[0][j].front().first, dq[1][j].front().first);
				}
			}
			//cout<<i<<" "<<j<<" "<<dp[i][j]<<endl;
			if(dp[i][j]==INFLL || i==N)	continue;
			int k = dp[i][j];
			add(0, j+1, r1, k);
			add(1, j, r2, k+1);
		}
	}
	for(int i=0; i<=P; i++){
		if(dp[N][i]<=Q)	return true;
	}
	return false;
}

int main(){
	scanf("%d%d%d", &N, &P, &Q);	
	v.pb(0);
	for(int i=1; i<=N; i++){
		ll x; scanf("%lld", &x);
		v.pb(x);
	}
	sort(v.begin(), v.end());
	v.erase(unique(v.begin(), v.end()), v.end());
	N = v.size()-1;
	ll s = 1LL, e = 1000000000LL, m;
	while(s<e){
		m = (s+e)/2LL;
		if(chk(m)){
			e = m;
		}else{
			s = m+1;
		}
	}
	printf("%lld", s);
}

Compilation message

watching.cpp: In function 'bool chk(ll)':
watching.cpp:51:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(r1<v.size()-1 && v[r1+1]<=v[i+1]+x-1LL){
         ~~^~~~~~~~~~~
watching.cpp:54:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(r2<v.size()-1 && v[r2+1]<=v[i+1]+2LL*x-1LL){
         ~~^~~~~~~~~~~
watching.cpp: In function 'int main()':
watching.cpp:82:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d", &N, &P, &Q); 
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
watching.cpp:85:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   ll x; scanf("%lld", &x);
         ~~~~~^~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 3448 KB Output is correct
2 Correct 5 ms 3064 KB Output is correct
3 Correct 4 ms 3064 KB Output is correct
4 Correct 10 ms 3448 KB Output is correct
5 Correct 10 ms 3448 KB Output is correct
6 Correct 10 ms 3448 KB Output is correct
7 Correct 9 ms 3448 KB Output is correct
8 Correct 10 ms 3448 KB Output is correct
9 Correct 9 ms 3448 KB Output is correct
10 Correct 10 ms 3504 KB Output is correct
11 Correct 10 ms 3448 KB Output is correct
12 Correct 10 ms 3448 KB Output is correct
13 Correct 9 ms 3448 KB Output is correct
14 Correct 9 ms 3448 KB Output is correct
15 Correct 9 ms 3448 KB Output is correct

Subtask #2
0 / 50.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1039 ms 18680 KB Time limit exceeded
2 Halted 0 ms 0 KB -