oj.uz

Submission #171683

# Submission time Handle Problem Language Result Execution time Memory
171683 2019-12-30T01:46:47 Z ToMmyDong Tents (JOI18_tents) C++11
100 / 100
 408 ms 59172 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i,n) for(int i=0;i<n;++i)
#define REP1(i,n) for(int i=1;i<=n;++i)
#define SZ(i) int(i.size())
#ifdef tmd
#define IOS()
#define debug(...) fprintf(stderr,"#%d: %s = ",__LINE__,#__VA_ARGS__),_do(__VA_ARGS__);
template<typename T> void _do(T &&x){cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T &&x, S &&...y){cerr<<x<<", ";_do(y...);}
template<typename It> ostream& _printRng(ostream &os,It bg,It ed)
{
    os<<"{";
    for(It it=bg;it!=ed;it++) {
        os<<(it==bg?"":",")<<*it;
    }
    os<<"}";
    return os;
}
template<typename T> ostream &operator << (ostream &os,vector<T> &v){return _printRng(os,v.begin(), v.end());}
template<typename T> void pary(T bg, T ed){_printRng(cerr,bg,ed);cerr<<endl;}
#else
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#define endl '\n'
#define debug(...)
#define pary(...)
#endif

const int MAXN = 3003;
const ll MOD = 1000000007;
const ll INF = 0x3f3f3f3f3f3f3f3f;

ll h, w;
ll dp[MAXN][MAXN];
ll fac[MAXN], pw[MAXN], rfac[MAXN];

ll mpow (ll bs, ll ep) {
    ll ret = 1;
    while (ep) {
        if (ep & 1) {
            ret = ret * bs % MOD;
        }
        bs = bs * bs % MOD;
        ep >>= 1;
    }
    return ret;
}

ll single (ll x, ll y) {
    if (dp[x][y] != 0) {
        return dp[x][y];
    }
    if (x == 0 || y == 0) {
        return dp[x][y] = 1;
    }
    return dp[x][y] = (single(x-1,y) + single(x-1,y-1)*4*y) % MOD;
}

ll cob (ll n, ll r) {
    return fac[n] * rfac[r] % MOD * rfac[n-r] % MOD;
}

ll pa[MAXN];
ll duo1 (ll len, ll one, ll two) {
    return cob(len,one) * cob(len-one,two*2) % MOD * pa[two] % MOD;
}

ll duo2 (ll len, ll one, ll two) {
    return fac[len] * rfac[len-(one+two*2)] % MOD * pw[two] % MOD;
}

/*********************GoodLuck***********************/
signed main () {
    IOS();

    cin >> h >> w;

    fac[0] = pw[0] = rfac[0] = 1;
    pa[0] = 1;

    ll r2 = mpow(2, MOD-2);
    REP1 (i, MAXN-1) {
        fac[i] = fac[i-1] * i % MOD;
        rfac[i] = mpow(fac[i], MOD - 2);
        pw[i] = pw[i-1] * r2 % MOD;
        pa[i] = pa[i-1] * (i*2-1) % MOD;
    }

    debug(cob(5,2));

    ll ans = MOD-1;
    REP (i, h+1) {
        REP (j, w+1) {
            if (i+j*2<=h && i*2+j <= w) {
                ll cur = single(h-(i+j*2),w-(i*2+j));
                cur = cur * duo1(h,i,j) % MOD;
                cur = cur * duo2(w,j,i) % MOD;
                ans = (ans + cur) % MOD;

                debug(i, j);
                assert(duo1(h,i,j)*duo2(w,j,i)%MOD == duo2(h,i,j)*duo1(w,j,i)%MOD);
            }
        }
    }


    cout << ans << endl;
}

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 504 KB Output is correct
2 Correct 3 ms 376 KB Output is correct
3 Correct 3 ms 632 KB Output is correct
4 Correct 3 ms 1272 KB Output is correct
5 Correct 3 ms 760 KB Output is correct
6 Correct 4 ms 1528 KB Output is correct
7 Correct 3 ms 888 KB Output is correct
8 Correct 4 ms 1656 KB Output is correct
9 Correct 3 ms 888 KB Output is correct
10 Correct 5 ms 2040 KB Output is correct
11 Correct 3 ms 504 KB Output is correct
12 Correct 7 ms 2168 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 504 KB Output is correct
2 Correct 3 ms 376 KB Output is correct
3 Correct 3 ms 632 KB Output is correct
4 Correct 3 ms 1272 KB Output is correct
5 Correct 3 ms 760 KB Output is correct
6 Correct 4 ms 1528 KB Output is correct
7 Correct 3 ms 888 KB Output is correct
8 Correct 4 ms 1656 KB Output is correct
9 Correct 3 ms 888 KB Output is correct
10 Correct 5 ms 2040 KB Output is correct
11 Correct 3 ms 504 KB Output is correct
12 Correct 7 ms 2168 KB Output is correct
13 Correct 3 ms 376 KB Output is correct
14 Correct 13 ms 9980 KB Output is correct
15 Correct 255 ms 47544 KB Output is correct
16 Correct 6 ms 1784 KB Output is correct
17 Correct 27 ms 7016 KB Output is correct
18 Correct 60 ms 13792 KB Output is correct
19 Correct 305 ms 53452 KB Output is correct
20 Correct 234 ms 42348 KB Output is correct
21 Correct 134 ms 25636 KB Output is correct
22 Correct 150 ms 30952 KB Output is correct
23 Correct 83 ms 26616 KB Output is correct
24 Correct 408 ms 59172 KB Output is correct
25 Correct 299 ms 49484 KB Output is correct
26 Correct 342 ms 54936 KB Output is correct
27 Correct 379 ms 57128 KB Output is correct