Submission #3537920


Source Code Expand

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

#define NDEBUG
#include <cassert>

typedef long long ll;
typedef long double Double;
typedef unsigned long long ull;
typedef pair<int,int> ii;
typedef pair<ll,ll> llll;
typedef pair<double,double> dd;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<long double> vD;

#define sz(a)  int((a).size())
#define pb  push_back
#define FOR(var,from,to) for(int var=(from);var<=(to);++var)
#define rep(var,n)  for(int var=0;var<(n);++var)
#define rep1(var,n)  for(int var=1;var<=(n);++var)
#define repC2(vari,varj,n)  for(int vari=0;vari<(n)-1;++vari)for(int varj=vari+1;varj<(n);++varj)
#define ALL(c)  (c).begin(),(c).end()
#define RALL(c)  (c).rbegin(),(c).rend()
#define tr(i,c)  for(auto i=(c).begin(); i!=(c).end(); ++i)
#define found(s,e)  ((s).find(e)!=(s).end())
#define mset(arr,val)  memset(arr,val,sizeof(arr))
#define mid(x,y) ((x)+((y)-(x))/2)
#define IN(x,a,b) ((a)<=(x)&&(x)<=(b))
#define cons make_pair


ll gcd(ll a, ll b) { while(a) swap(a, b%=a); return b; }

const ll MOD=1000000007LL;

ll ADD(ll x, ll y) { return (x+y) % MOD; }
ll SUB(ll x, ll y) { return (x-y+MOD) % MOD; }
ll MUL(ll x, ll y) { return x*y % MOD; }
ll POW(ll x, ll e) { ll v=1; for(; e; x=MUL(x,x), e>>=1) if (e&1) v = MUL(v,x); return v; }
ll DIV(ll x, ll y) { /*assert(y%MOD!=0);*/ return MUL(x, POW(y, MOD-2)); }

vector<int> hs;

ll solve(int H, int W, int K) {
    int P = 1 << (W - 1);
    rep(p, P) {
        bool good = true;
        for (int i = 0, m = 3; i < W -2; ++i, m <<= 1) {
            if ((p & m)==m) { good = false; break; }
        }
        if (good) hs.pb(p);
    }
    vector<vector<int>> pat(W, vi(W, 0));
    for (int a=0,ma=1;a<W;++a,ma<<=1) {
        int cnt = 0;
        for (int h : hs) {
            bool good = true;
            if (a>=1 && (h&(ma>>1))) {
                good = false;
                continue;
                 }
            if (a < W-1 && (h&ma)) {
                good = false;
                continue;
            }
            if (good) {
                ++cnt;
            }
        }
        pat[a][a] = cnt;

        if (a<W-1 ) {
            cnt = 0;
            for (int h : hs) {
                if (h & ma) {
                    ++cnt;
                }
            }
            pat[a][a + 1] = pat[a + 1][a] = cnt;
        }

        for (int b = a + 2; b<W; ++b) {
            pat[a][b] = pat[b][a] = 0;
        }
     }

     vector<ll> dp(W, 0);
     dp[0] = 1;
     rep(i, H) {
         vector<ll> dp2(W, 0);
         rep(a, W) rep(b, W) { dp2[b] = ADD(dp2[b], MUL(dp[a], pat[a][b])); }
         dp = dp2;
     }

     return dp[K - 1];
}

int main() {
    int H, W, K;
    cin >> H >> W >> K;
    assert(IN(H, 1, 100));
    assert(IN(W, 1, 8));
    assert(IN(K, 1, W));

    cout << solve(H,W,K) << endl;

    return 0;
}

Submission Info

Submission Time
Task D - Number of Amidakuji
User naoya_t
Language C++14 (GCC 5.4.1)
Score 400
Code Size 3093 Byte
Status AC
Exec Time 1 ms
Memory 256 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 400 / 400
Status
AC × 6
AC × 16
Set Name Test Cases
Sample sample_01.txt, sample_02.txt, sample_03.txt, sample_04.txt, sample_05.txt, sample_06.txt
All in01.txt, in02.txt, in03.txt, in04.txt, in05.txt, in06.txt, in07.txt, in08.txt, in09.txt, in10.txt, sample_01.txt, sample_02.txt, sample_03.txt, sample_04.txt, sample_05.txt, sample_06.txt
Case Name Status Exec Time Memory
in01.txt AC 1 ms 256 KB
in02.txt AC 1 ms 256 KB
in03.txt AC 1 ms 256 KB
in04.txt AC 1 ms 256 KB
in05.txt AC 1 ms 256 KB
in06.txt AC 1 ms 256 KB
in07.txt AC 1 ms 256 KB
in08.txt AC 1 ms 256 KB
in09.txt AC 1 ms 256 KB
in10.txt AC 1 ms 256 KB
sample_01.txt AC 1 ms 256 KB
sample_02.txt AC 1 ms 256 KB
sample_03.txt AC 1 ms 256 KB
sample_04.txt AC 1 ms 256 KB
sample_05.txt AC 1 ms 256 KB
sample_06.txt AC 1 ms 256 KB