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Submission #988371

# Submission time Handle Problem Language Result Execution time Memory
988371 2024-05-24T14:45:42 Z GrindMachine Kangaroo (CEOI16_kangaroo) C++17
100 / 100
 37 ms 31836 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

/*

refs:
https://codeforces.com/blog/entry/47764?#comment-704139

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

void solve(int test_case)
{
    ll n,cs,cf; cin >> n >> cs >> cf;
    ll dp[n+5][n+5];
    memset(dp,0,sizeof dp);
    dp[1][0] = 1;

    rep1(i,n){
        rep(j,n+1){
            dp[i][j] %= MOD;

            if(i == cs or i == cf){
                ll ways = j;
                if(i > min(cs,cf)){
                    if(i != n){
                        ways--;
                    }
                }

                // new
                dp[i+1][j+1] += dp[i][j];

                // merge
                dp[i+1][j] += dp[i][j]*ways;
            }
            else{
                // new
                dp[i+1][j+1] += dp[i][j];

                // merge
                if(j){
                    ll ways = 0;
                    ll spl = 0;

                    // cs on the left
                    if(i > cs){
                        ways += j-1;
                        spl++;
                    }

                    // cf on the right
                    if(i > cf){
                        ways += j-1;
                        spl++;
                    }

                    // cs on left, cf on right
                    if(spl == 2){
                        if(i == n) ways--;
                        else ways -= 2;
                    }

                    // no spl on both sides
                    ll non_spl = j-spl;
                    if(non_spl >= 2){
                        ways += non_spl*(non_spl-1);
                    }

                    dp[i+1][j-1] += ways*dp[i][j];
                }
            }
        }
    }

    ll ans = dp[n+1][1];
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 360 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 1 ms 348 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 1 ms 348 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 360 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 1 ms 348 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 1 ms 348 KB Output is correct
12 Correct 1 ms 604 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 1 ms 604 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 604 KB Output is correct
17 Correct 2 ms 860 KB Output is correct
18 Correct 1 ms 604 KB Output is correct
19 Correct 1 ms 604 KB Output is correct
20 Correct 1 ms 604 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 360 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 1 ms 348 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 1 ms 348 KB Output is correct
12 Correct 1 ms 604 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 1 ms 604 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 604 KB Output is correct
17 Correct 2 ms 860 KB Output is correct
18 Correct 1 ms 604 KB Output is correct
19 Correct 1 ms 604 KB Output is correct
20 Correct 1 ms 604 KB Output is correct
21 Correct 4 ms 3676 KB Output is correct
22 Correct 4 ms 4232 KB Output is correct
23 Correct 5 ms 4972 KB Output is correct
24 Correct 33 ms 31784 KB Output is correct
25 Correct 37 ms 31836 KB Output is correct
26 Correct 34 ms 31824 KB Output is correct
27 Correct 37 ms 31568 KB Output is correct
28 Correct 18 ms 18012 KB Output is correct