oj.uz

Submission #56564

# Submission time Handle Problem Language Result Execution time Memory
56564 2018-07-11T17:44:58 Z Benq Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 145 ms 52456 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 2005;

int N,cs,cf;
int A[MX][MX], a[MX][MX];
int AA[MX][MX], aa[MX][MX];
int D[MX][MX], d[MX][MX];

int ad(int a, int b) { return (a+b)%MOD; }
int sub(int a, int b) { return (a-b+MOD)%MOD; }

int getD(int n, int i, int j);

int getA(int n, int i, int j) { // what about getA(n,0,j)?
    if (i == j || i < 0 || i > n-1 || j < 0 || j > n-1) return 0;
    if (i == 0) {
        if (aa[n][j]) return AA[n][j];
        aa[n][j] = 1;
        if (j == 1) {
            if (n == 2) AA[n][j] = 1;
            else if (n % 2 == 0) AA[n][j] = 0;
            else {
                FOR(i,1,n-1) AA[n][j] = ad(AA[n][j],getA(n-1,0,i));
            }
        } else {
            if (n % 2 == 1) AA[n][j] = sub(getA(n,0,j-1),getA(n-1,0,j-1));
            else AA[n][j] = ad(getA(n,0,j-1),getA(n-1,0,j-1));
        }
        // cout << "A " << n << " " << i << " " << j << " " << AA[n][j] << "\n";
        return AA[n][j];
    }
    if (a[i][j]) return A[i][j];
    
    a[i][j] = 1;
    A[i][j] = sub(getA(n,i-1,j),getD(n-1,i-1,j-1));
    // cout << "A " << n << " " << i << " " << j << " " << A[i][j] << " " << getA(n,i-1,j) << " " <<  getD(n-1,i-1,j-1) << "\n";
    return A[i][j];
}

int getD(int n, int i, int j) { 
    if (i == j || i <= 0 || i > n-1 || j < 0 || j > n-1) return 0;
    if (d[i][j]) return D[i][j];
    d[i][j] = 1;
    D[i][j] = ad(getD(n,i-1,j),getA(n-1,i-1,j-1));
    // cout << "D " << n << " " << i << " " << j << " " << D[i][j] << "\n";
    return D[i][j];
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> N >> cs >> cf;
    if (cs > cf) swap(cs,cf);
    cs --, cf --;
    // cout << getA(N,cs,cf) << " " << getD(N,cs,cf) << "\n";
    cout << ad(getA(N,cs,cf),getD(N,cs,cf));
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 644 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 644 KB Output is correct
3 Correct 3 ms 992 KB Output is correct
4 Correct 2 ms 1356 KB Output is correct
5 Correct 3 ms 1648 KB Output is correct
6 Correct 3 ms 1648 KB Output is correct
7 Correct 3 ms 1648 KB Output is correct
8 Correct 3 ms 1648 KB Output is correct
9 Correct 3 ms 1648 KB Output is correct
10 Correct 4 ms 1648 KB Output is correct
11 Correct 4 ms 1652 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 644 KB Output is correct
3 Correct 3 ms 992 KB Output is correct
4 Correct 2 ms 1356 KB Output is correct
5 Correct 3 ms 1648 KB Output is correct
6 Correct 3 ms 1648 KB Output is correct
7 Correct 3 ms 1648 KB Output is correct
8 Correct 3 ms 1648 KB Output is correct
9 Correct 3 ms 1648 KB Output is correct
10 Correct 4 ms 1648 KB Output is correct
11 Correct 4 ms 1652 KB Output is correct
12 Correct 8 ms 3704 KB Output is correct
13 Correct 5 ms 3704 KB Output is correct
14 Correct 11 ms 6144 KB Output is correct
15 Correct 5 ms 6144 KB Output is correct
16 Correct 7 ms 6144 KB Output is correct
17 Correct 7 ms 6144 KB Output is correct
18 Correct 5 ms 6144 KB Output is correct
19 Correct 6 ms 6144 KB Output is correct
20 Correct 6 ms 6144 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 644 KB Output is correct
3 Correct 3 ms 992 KB Output is correct
4 Correct 2 ms 1356 KB Output is correct
5 Correct 3 ms 1648 KB Output is correct
6 Correct 3 ms 1648 KB Output is correct
7 Correct 3 ms 1648 KB Output is correct
8 Correct 3 ms 1648 KB Output is correct
9 Correct 3 ms 1648 KB Output is correct
10 Correct 4 ms 1648 KB Output is correct
11 Correct 4 ms 1652 KB Output is correct
12 Correct 8 ms 3704 KB Output is correct
13 Correct 5 ms 3704 KB Output is correct
14 Correct 11 ms 6144 KB Output is correct
15 Correct 5 ms 6144 KB Output is correct
16 Correct 7 ms 6144 KB Output is correct
17 Correct 7 ms 6144 KB Output is correct
18 Correct 5 ms 6144 KB Output is correct
19 Correct 6 ms 6144 KB Output is correct
20 Correct 6 ms 6144 KB Output is correct
21 Correct 16 ms 10788 KB Output is correct
22 Correct 17 ms 12076 KB Output is correct
23 Correct 19 ms 12076 KB Output is correct
24 Correct 85 ms 38572 KB Output is correct
25 Correct 145 ms 52456 KB Output is correct
26 Correct 100 ms 52456 KB Output is correct
27 Correct 72 ms 52456 KB Output is correct
28 Correct 52 ms 52456 KB Output is correct