C. Anya and Ghosts
time limit per test
memory limit per test
input
output
m ghosts tonight. Anya has lots of candles prepared for the visits, each candle can produce light for exactly t seconds. It takes the girl one second to light one candle. More formally, Anya can spend one second to light one candle, then this candle burns for exactly t
m ghosts Anya knows the time at which it comes: the i-th visit will happen wi seconds after midnight, all wi's are distinct. Each visit lasts exactly one second.
r candles are burning? Anya can start to light a candle at any time that is integer number of seconds from midnight, possibly, at the time before midnight. That means, she can start to light a candle integer number of seconds before midnight or integer number of seconds after a midnight, or in other words in any integer moment of time.
Input
m, t, r (1 ≤ m, t, r ≤ 300), representing the number of ghosts to visit Anya, the duration of a candle's burning and the minimum number of candles that should burn during each visit.
m space-separated numbers wi (1 ≤ i ≤ m, 1 ≤ wi), the i-th of them repesents at what second after the midnight the i-th ghost will come. All wi's are distinct, they follow in the strictly increasing order.
Output
r
- 1.
Sample test(s)
input
1 8 3 10
output
3
input
2 10 1 5 8
output
1
input
1 1 3 10
output
-1
Note
Anya can start lighting a candle in the same second with ghost visit. But this candle isn't counted as burning at this visit.
It takes exactly one second to light up a candle and only after that second this candle is considered burning; it means that if Anya starts lighting candle at moment x, candle is buring from second x + 1 to second x + t inclusively.
3-rd, 5-th and 7-th seconds after the midnight.
In the second sample test one candle is enough. For example, Anya can start lighting it one second before the midnight.
- 1, since during each second at most one candle can burn but Anya needs three candles to light up the room at the moment when the ghost comes.
贪心，尽可能推迟点蜡烛的时间
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<functional>
#include<iostream>
#include<cmath>
#include<cctype>
#include<ctime>
using namespace std;
#define For(i,n) for(int i=1;i<=n;i++)
#define Fork(i,k,n) for(int i=k;i<=n;i++)
#define Rep(i,n) for(int i=0;i<n;i++)
#define ForD(i,n) for(int i=n;i;i--)
#define RepD(i,n) for(int i=n;i>=0;i--)
#define Forp(x) for(int p=pre[x];p;p=next[p])
#define Forpiter(x) for(int &p=iter[x];p;p=next[p])
#define Lson (x<<1)
#define Rson ((x<<1)+1)
#define MEM(a) memset(a,0,sizeof(a));
#define MEMI(a) memset(a,127,sizeof(a));
#define MEMi(a) memset(a,128,sizeof(a));
#define INF (2139062143)
#define F (100000007)
#define MAXN (300+10)
long long mul(long long a,long long b){return (a*b)%F;}
long long add(long long a,long long b){return (a+b)%F;}
long long sub(long long a,long long b){return (a-b+(a-b)/F*F+F)%F;}
typedef long long ll;
int m,l,r,w[MAXN];
int q[MAXN]={0};
int main()
{
// freopen("Ghosts.in","r",stdin);
// freopen(".out","w",stdout);
cin>>m>>l>>r;
For(i,m) scanf("%d",&w[i]);
if (l<r)
{
cout<<"-1"<<endl;
return 0;
}
int L=1,R=0;
For(i,m)
{
int t=w[i];
while (L<=R&&q[L]<t-l) L++;
int size=R-L+1;
if (size<r)
{
int p=r-size;
Fork(j,t-p,t-1) q[++R]=j;
}
}
cout<<R<<endl;
return 0;
}
