Submission #448683

#	Time	Username	Problem	Language	Result	Execution time	Memory
448683		ymm	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	578 ms	5280 KiB

skyscraper

///
///    I have a dream and a piano
///

#define _USE_MATH_DEFINES
#define FAST ios::sync_with_stdio(false),cin.tie(0);
#include <bits/stdc++.h>
#define Loop(x, l, r) for(int x = (l); x < (r); ++x)
#define LoopR(x, l, r) for(int x = (r)-1; x >= (l); --x)
#define all(x) x.begin(), x.end()
#define Kill(x) exit((cout << (x) << '\n', 0))
#define YN(flag) ((flag)? "YES": "NO")
#define F first
#define S second
typedef          long long   ll;
typedef unsigned long long  ull;
typedef std::pair<int,int>  pii;
typedef std::pair<ll ,ll >  pll;
using namespace std;

const int N = 105;
const int L = 1005;
const int mod = 1e9 + 7;
ll dp1[N][L][3];
ll dp2[N][L][3];
int a[N];
int n, l;

int main()
{
    FAST;
    cin >> n >> l;
    Loop(i,0,n) cin >> a[i];
    sort(a, a+n);
    dp1[0][0][0] = 1;
    Loop(i,0,n)
    {
        Loop(k,0,N)
            Loop(l,0,L)
                Loop(r,0,3)
                {
                    ll x = i? a[i] - a[i-1]: a[0];
                    x = (2*k - r)*x + l;
                    if(x < 0 || x >= L) continue;

                    if(k > 0) dp2[k-1][x][r] += (k-1) * dp1[k][l][r];
                    if(true) dp2[k][x][r] += (2*k-r) * dp1[k][l][r];
                    if(r+!k < 2) dp2[k+!k][x][r+1+!k] += (2-r-!k) * dp1[k][l][r];
                    if(r < 2  && k < N-1) dp2[k+1][x][r+1] += (2-r) * dp1[k][l][r];
                    if(k < N-1) dp2[k+1][x][r] += (k+1-r) * dp1[k][l][r];
                }

        Loop(k,0,N)
            Loop(l,0,L)
                Loop(r,0,3)
                    dp1[k][l][r] = dp2[k][l][r] % mod,
                    dp2[k][l][r] = 0;
    }
    ll ans = 0;
    Loop(i,0,l+1)
        ans += dp1[1][i][2];
    cout << ans%mod << '\n';
}

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