Submission #31362

#	Time	Username	Problem	Language	Result	Execution time	Memory
31362		tatatan	Skyscraper (JOI16_skyscraper)	C++11	100 / 100	693 ms	174612 KiB

skyscraper

#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define pii pair<int,int>
#define LL long long
#define st first
#define nd second
#define endl '\n'
using namespace std;

int n,L,dp[105][105][2][2][1001],a[105],mod=1e9+7;

void add(int &x,LL y) {

	y%=mod;
	x+=y;
	if(x>=mod)
		x-=mod;

}

int f(int x,int cnt,int l,int r,int sum) {

	if(x>0)
		sum+=(cnt*2+l+r)*(a[x]-a[x-1]);
	if(sum>L||cnt<0)
		return 0;
	if(x==n-1)
		return (cnt==0);
	int &ret=dp[x][cnt][l][r][sum];
	if(ret!=-1)
		return ret;
	ret=0;
	add(ret,f(x+1,cnt,1,r,sum));
	add(ret,1LL*f(x+1,cnt-1,1,r,sum)*cnt);
	add(ret,f(x+1,cnt,l,1,sum));
	add(ret,1LL*f(x+1,cnt-1,l,1,sum)*cnt);
	add(ret,f(x+1,cnt+1,l,r,sum));
	add(ret,1LL*f(x+1,cnt,l,r,sum)*cnt*2);
	add(ret,1LL*f(x+1,cnt-1,l,r,sum)*cnt*(cnt-1));
	return ret;

}

int main() {

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	memset(dp,-1,sizeof dp);
	cin>>n>>L;
	for(int i=0;i<n;++i)
		cin>>a[i];
	sort(a,a+n);
	cout<<f(0,0,0,0,0)<< endl;

}	

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 80 / 80