Submission #1075320

#	Time	Username	Problem	Language	Result	Execution time	Memory
1075320		Boycl07	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	70 ms	3420 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define rep(i, n) for(int i = 1; (i) <= (n); ++i)
#define forn(i, l, r) for(int i = (l); i <= (r); ++i)
#define ford(i, r, l) for(int i = (r); i >= (l); --i)
#define FOR(i, n) for(int i = 0; i < (n); ++i)
#define FORD(i, n) for(int i = ((n) - 1); i >= 0; --i)
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define endl "\n"
#define task "BAI1"
#define sz(a) int(a.size())
#define C(x, y) make_pair(x, y)
#define all(a) (a).begin(), (a).end()
#define bit(i, mask) (mask >> i & 1)

template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }

inline int readInt()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();int n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline ll readLong()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();ll  n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline string readString() {char c;while(c=getchar(),c==' '||c=='\n'||c=='\t');string s({c});while(c=getchar(),c!=EOF&&c!=' '&&c!='\n'&&c!='\t')s+=c;return s;}

const int N = 1e2 + 3;
const int M = 1e3 + 3;
const int LOG = 50;
const int MOD = 1e9 + 7;
const ll INF = 1e18;

int n, L;

int dp[2][N][M][4];
int a[N];
void add(int &x, int y)
{
    x += y;
    if(x >= MOD) x -= MOD;
}

int mul(int x, int y) {return 1ll * x * y % MOD;}

void solve()
{
    cin >> n >> L;
    rep(i, n) cin >> a[i];
    if(n == 1) return cout << 1, void();
    sort(a + 1, a + 1 + n);
    int f = 0;
    dp[0][1][0][0] = 1;
    dp[0][1][0][1] = 2;
    forn(i, 2, n)
    {
        for(int num_cc = 1; num_cc <= n; ++num_cc)
            for(int sum = 0; sum <= L; ++sum)
                for(int num_ends = 0; num_ends <= 2; ++num_ends) dp[f ^ 1][num_cc][sum][num_ends] = 0;

        for(int num_cc = 1; num_cc <= n; ++num_cc)
            for(int sum = 0; sum <= L; ++sum)
                for(int num_ends = 0; num_ends <= 2; ++num_ends)
                if(dp[f][num_cc][sum][num_ends]) {
                    int new_sum = sum + 1ll * (a[i] - a[i - 1]) * (2 * num_cc - num_ends);
                    if(new_sum <= L)
                    {
                        #define trans(x, y, z) add(dp[f ^ 1][num_cc + x][new_sum][num_ends + y], mul(dp[f][num_cc][sum][num_ends], z));


                        trans(-1, 0, num_cc - 1); /// merge cc
                        trans(1, 0, num_cc + 1 - num_ends); /// create cc

                        trans(0, 0, 2 * num_cc - num_ends); /// append cc

                        trans(1, 1, 2 - num_ends); /// create end
                        trans(0, 1, 2 - num_ends); /// append end
                    }
                }
        f ^= 1;
    }

    int res = 0;
    for(int sum = 0; sum <= L; ++sum) add(res, dp[f][1][sum][2]);
    cout << res;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int TC = 1;

    if(fopen("note.inp", "r"))
    {
        freopen("note.inp", "r", stdin);
        freopen("note.out", "w", stdout);
    }

    while(TC--)
    {
        solve();
        cout << endl;
    }

    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:100:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  100 |         freopen("note.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:101:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |         freopen("note.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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