Submission #1138543

#	Time	Username	Problem	Language	Result	Execution time	Memory
1138543		SmuggingSpun	Skyscraper (JOI16_skyscraper)	C++20	20 / 100	202 ms	91108 KiB

skyscraper

#include<bits/stdc++.h>
#define taskname "C"
using namespace std;
const int mod = 1e9 + 7;
void add(int& a, int b){
	if((a += b) >= mod){
		a -= mod;
	}
}
int n, L;
namespace sub1{
	void solve(){
		vector<int>a(n), p(n);
		for(int& x : a){
			cin >> x;
		}
		int ans = 0;
		iota(p.begin(), p.end(), 0);
		do{
			int sum = 0;
			for(int i = 1; i < n; i++){
				sum += abs(a[p[i]] - a[p[i - 1]]);
			}
			if(sum <= L){
				ans++;
			}
		} while(next_permutation(p.begin(), p.end()));
		cout << ans;
	}
}
namespace sub2{
	int dp[1 << 14][14][101];
	void solve(){
		vector<int>a(n);
		for(int& x : a){
			cin >> x;
		}
		memset(dp, 0, sizeof(dp));
		for(int mask = 1; mask < (1 << n); mask++){
			vector<int>bit;
			for(int i = 0; i < n; i++){
				if(1 << i & mask){
					bit.emplace_back(i);
				}
			}
			if(bit.size() == 1){
				dp[mask][bit[0]][0] = 1;
			}
			else{
				for(int& i : bit){
					for(int& j : bit){
						if(i != j){
							for(int d = abs(a[i] - a[j]), k = d; k <= L; k++){
								add(dp[mask][i][k], dp[mask ^ (1 << i)][j][k - d]);
							}
						}
					}
				}
			}
		}
		int ans = 0;
		for(int i = 0; i < n; i++){
			for(int j = 0; j <= L; j++){
				add(ans, dp[(1 << n) - 1][i][j]);
			}
		}
		cout << ans;
	}
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
	cin >> n >> L;
	if(n <= 8){
		sub1::solve();
	}
	else if(n <= 14 && L <= 100){
		sub2::solve();
	}
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:73:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 80