Submission #528029

#	Time	Username	Problem	Language	Result	Execution time	Memory
528029		tphuc2908	Skyscraper (JOI16_skyscraper)	C++14	20 / 100	2082 ms	426312 KiB

skyscraper

#include<bits/stdc++.h>

using namespace std;
//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,fma")
//#pragma GCC optimization ("unroll-loops")
#define rep(i, x, y) for(int i = x; i <= y; ++i)
#define repi(i,x,y) for(int i = x; i >= y; --i)
#define ci(x) int x; cin>> x
#define TC(t) ci(t); while(t--)
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define cii(x, y) ci(x); ci(y)
#define ciii(x, y, z) ci(x); ci(y); ci(z)
#define mp make_pair
//#define int long long
typedef long long ll;
typedef vector<int> vi;
const int N = 1e2 + 5;
const int NN = 16 + 15;
const int mod = 1e9+7;
const int mod1 = 1e9 + 9;
const int pi = 31;
const ll inf = 1e15 + 6;
const int block = 500;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};

void readfile(){
    #ifdef ONLINE_JUDGE
    #else
        freopen("text.inp", "r", stdin);
    #endif // ONLINE_JUDGE
//    freopen("text.inp", "r", stdin);
//    freopen("template.out", "w", stdout);
}

int n, L;
int a[N];

void inp(){
    cin >> n >> L;
    for(int i = 1; i <= n; ++i) cin >> a[i];
    sort(a + 1, a + n + 1);
}

int add(int x, int y){
    x += y;
    while(x < 0) x += mod;
    while(x >= mod) x -= mod;
    return x;
}

int mul(int x, int y){
    return (x * 1LL * y) % mod;
}

unordered_map<int,int> f[N][N][3];
unordered_set<int> s[N][N][3];

void process(){
    f[1][1][0][-2*a[1]] = 1;
    f[1][1][1][-a[1]] = 2;
    f[1][1][2][0] = 1;
    s[1][1][0].insert(-2*a[1]);
    s[1][1][1].insert(-a[1]);
    s[1][1][2].insert(0);
    for(int i = 1; i < n; ++i){
        for(int j = 1; j <= i; ++j){
            for(int t = 0; t <= 2; ++t){
                for(int sum : s[i][j][t]){
                    if(j >= 2){
                        // merge two cc
                        f[i + 1][j - 1][t][sum + 2*a[i + 1]] = add(f[i + 1][j - 1][t][sum + 2*a[i + 1]], mul(f[i][j][t][sum], j - 1));
                        s[i + 1][j - 1][t].insert(sum + 2*a[i + 1]);
                    }
                    if(t==0){ // not having any at the end or beginning
                        // new cc
                        f[i + 1][j + 1][0][sum + -2*a[i + 1]] = add(f[i + 1][j + 1][0][sum + -2*a[i + 1]], mul(f[i][j][t][sum], j + 1));
                        f[i + 1][j + 1][1][sum + -a[i + 1]] = add(f[i + 1][j + 1][1][sum + -a[i + 1]], mul(f[i][j][t][sum], 2)); // new cc but at the end or beginning
                        s[i + 1][j + 1][0].insert(sum - 2*a[i + 1]);
                        s[i + 1][j + 1][1].insert(sum - a[i + 1]);
                        // attach to existing cc
                        f[i + 1][j][0][sum] = add(f[i + 1][j][0][sum], mul(f[i][j][t][sum], 2*j));
                        s[i + 1][j][0].insert(sum);
                        f[i + 1][j][1][sum + a[i + 1]] = add(f[i + 1][j][1][sum + a[i + 1]], mul(f[i][j][t][sum], 2)); // increasing one endpoint
                        s[i + 1][j][1].insert(sum + a[i + 1]);
                    }
                    else if(t==1){
                            // new cc
                            f[i + 1][j + 1][1][sum -2*a[i + 1]] = add(f[i + 1][j + 1][1][sum - 2*a[i + 1]], mul(f[i][j][t][sum], j));
                            f[i + 1][j + 1][2][sum - a[i + 1]] = add(f[i + 1][j + 1][2][sum - a[i + 1]], f[i][j][t][sum]); // new cc but at one endpoint
                            s[i + 1][j + 1][1].insert(sum - 2*a[i + 1]);
                            s[i + 1][j + 1][2].insert(sum - a[i + 1]);
                            // attach to existing cc
                            f[i + 1][j][1][sum] = add(f[i + 1][j][1][sum], mul(f[i][j][t][sum], 2*j - 1));
                            f[i + 1][j][2][sum + a[i + 1]] = add(f[i + 1][j][2][sum + a[i + 1]], f[i][j][t][sum]); // increasing one endpoint to two endpoints
                            s[i + 1][j][1].insert(sum);
                            s[i + 1][j][2].insert(sum + a[i + 1]);
                        }
                        else{
                            if(j >= 2){
                                // new cc
                                f[i + 1][j + 1][2][sum - 2*a[i + 1]] = add(f[i + 1][j + 1][2][sum - 2*a[i + 1]], mul(f[i][j][t][sum], j - 1));
                                s[i + 1][j + 1][2].insert(sum - 2*a[i + 1]);
                                // attach to existing cc
                                f[i + 1][j][2][sum] = add(f[i + 1][j][2][sum], mul(f[i][j][t][sum], 2*j - 2));
                                s[i + 1][j][2].insert(sum);
                            }
                        }
                }
            }
        }
    }
    int res = 0;
    for(int i = 0; i <= L; ++i)
        res = add(res, f[n][1][2][i]);
    cout << res;
}

int main() {
    //readfile();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    inp();
    process();
    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'void readfile()':
skyscraper.cpp:34:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |         freopen("text.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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