oj.uz

Submission #56568

# Submission time Handle Problem Language Result Execution time Memory
56568 2018-07-11T18:05:22 Z Benq Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 62 ms 16296 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, ce, dp[MX][MX];

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

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> N >> cs >> ce;
    int cnt = 0;
    dp[0][0] = 1;
    FOR(i,1,N+1) {
        FOR(j,1,N+1) {
            if (i == cs || i == ce) {
                dp[i][j] = ad(dp[i][j],dp[i-1][j-1]); // down
                dp[i][j] = ad(dp[i][j],dp[i-1][j]); // up 
            } else {
                dp[i][j] = ad(dp[i][j],mul(dp[i-1][j-1],j-cnt)); // add new 
                dp[i][j] = ad(dp[i][j],mul(dp[i-1][j+1],j)); // delete old
            }
        }
        if (i == cs || i == ce) cnt ++;
    }
    cout << dp[N][1];
}

/* 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 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 428 KB Output is correct
4 Correct 3 ms 556 KB Output is correct
5 Correct 3 ms 596 KB Output is correct
6 Correct 2 ms 600 KB Output is correct
7 Correct 2 ms 644 KB Output is correct
8 Correct 2 ms 672 KB Output is correct
9 Correct 2 ms 672 KB Output is correct
10 Correct 3 ms 800 KB Output is correct
11 Correct 3 ms 800 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 428 KB Output is correct
4 Correct 3 ms 556 KB Output is correct
5 Correct 3 ms 596 KB Output is correct
6 Correct 2 ms 600 KB Output is correct
7 Correct 2 ms 644 KB Output is correct
8 Correct 2 ms 672 KB Output is correct
9 Correct 2 ms 672 KB Output is correct
10 Correct 3 ms 800 KB Output is correct
11 Correct 3 ms 800 KB Output is correct
12 Correct 4 ms 1468 KB Output is correct
13 Correct 4 ms 1468 KB Output is correct
14 Correct 4 ms 1468 KB Output is correct
15 Correct 4 ms 1516 KB Output is correct
16 Correct 4 ms 1516 KB Output is correct
17 Correct 3 ms 1640 KB Output is correct
18 Correct 4 ms 1640 KB Output is correct
19 Correct 4 ms 1640 KB Output is correct
20 Correct 4 ms 1640 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 428 KB Output is correct
4 Correct 3 ms 556 KB Output is correct
5 Correct 3 ms 596 KB Output is correct
6 Correct 2 ms 600 KB Output is correct
7 Correct 2 ms 644 KB Output is correct
8 Correct 2 ms 672 KB Output is correct
9 Correct 2 ms 672 KB Output is correct
10 Correct 3 ms 800 KB Output is correct
11 Correct 3 ms 800 KB Output is correct
12 Correct 4 ms 1468 KB Output is correct
13 Correct 4 ms 1468 KB Output is correct
14 Correct 4 ms 1468 KB Output is correct
15 Correct 4 ms 1516 KB Output is correct
16 Correct 4 ms 1516 KB Output is correct
17 Correct 3 ms 1640 KB Output is correct
18 Correct 4 ms 1640 KB Output is correct
19 Correct 4 ms 1640 KB Output is correct
20 Correct 4 ms 1640 KB Output is correct
21 Correct 12 ms 4860 KB Output is correct
22 Correct 13 ms 5372 KB Output is correct
23 Correct 13 ms 5884 KB Output is correct
24 Correct 62 ms 16296 KB Output is correct
25 Correct 55 ms 16296 KB Output is correct
26 Correct 59 ms 16296 KB Output is correct
27 Correct 62 ms 16296 KB Output is correct
28 Correct 49 ms 16296 KB Output is correct