Submission #1029362

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029362		codefox	Skyscraper (JOI16_skyscraper)	C++14	100 / 100	205 ms	16988 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

#pragma GCC optimize("Ofast")

#define int long long
const int mod = 1e9 + 7;

int32_t main()
{
    int n, l;
    cin >> n >> l;
    if (n==1)
    {
        cout << 1;
        return 0;
    }
    vector<int> nums(n);
    for (int i = 0; i < n; i++)
    {
        cin >> nums[i];
    }
    sort(nums.begin(), nums.end());
    vector<vector<vector<vector<int>>>> dp(2, vector<vector<vector<int>>>(l+1, vector<vector<int>>(n+1, vector<int>(3, 0))));
    dp[1][0][1][0] = 1;
    dp[1][0][1][1] = 2;
    for (int i = 1; i < n; i++)
    {
        int ii = (i+1)%2;
        int cc = (i)%2;
        dp[ii].assign(l+1, vector<vector<int>>(n+1, vector<int>(3, 0)));
        for (int j = 0; j <= l; j++)
        {
            for (int k = 1; k <= i; k++)
            {
                for (int m =0; m < 3; m++)
                {
                    int nsum = j;
                    nsum = j+(k*2-m)*(nums[i]-nums[i-1]);
                    if(nsum > l) continue;
                    dp[ii][nsum][k][m] += dp[cc][j][k][m]*(k*2-m);
                    dp[ii][nsum][k-1][m] += dp[cc][j][k][m]*(k-1);
                    dp[ii][nsum][k+1][m] += dp[cc][j][k][m]*(k+1-m);
                    if(m!=2)
                    {
                        dp[ii][nsum][k+1][m+1] += dp[cc][j][k][m]*(2-m);
                        if(k) dp[ii][nsum][k][m+1] += dp[cc][j][k][m]*(2-m);
                        dp[ii][nsum][k+1][m+1]%=mod;
                        dp[ii][nsum][k][m+1]%=mod;
                    }
                    dp[ii][nsum][k][m]%=mod;
                    dp[ii][nsum][k-1][m]%=mod;
                    dp[ii][nsum][k+1][m]%=mod;
                }
            }
        }
    }
    int sum = 0;
    for (int i = 0; i <= l; i++)
    {
        sum += dp[n%2][i][1][2];
        sum%=mod;
    }
    cout << sum;
    return 0;
}

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