Submission #682724

#	Time	Username	Problem	Language	Result	Execution time	Memory
682724		quinque	Kangaroo (CEOI16_kangaroo)	C++17	0 / 100	1 ms	340 KiB

kangaroo

#include <stdlib.h>
#include <time.h>
#include <algorithm>
#include <bitset>
#include <chrono>
#include <climits>
#include <cmath>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <stdio.h>
#include <string.h>
#include <vector>
#include <unordered_map>
#define ll long long
#define ull unsigned long long
#define unit unsigned int
#define ld double
#define F first
#define S second
// chrono::system_clock::now().time_since_epoch().count());

using namespace std;
const int N = 2e3 + 10, IINF = 1e7, LOG = 19, K = 73;
const ll M = 1e9 + 7, INF = 1e14 + 214;
int pls(int a, int b){
    a += b;
    while(a >= M)
        a -= M;
    while(a <= 0)
        a += M;
    return a;
}
int mult(int a, int b){
    return 1ll * a * b % M;
}

int dp[N][N];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n, a, b;
    cin >> n >> a >> b;
    dp[1][1] = 1;
    for (int i = 2; i <= n; i ++){
        for (int j = 1; j <= n; j ++){
            if (a == i || b == i)
                dp[i][j] = pls(dp[i - 1][j - 1], dp[i - 1][j]);
            else {
                int f1 = mult(dp[i - 1][j + 1], j);
                int f2 = mult(dp[i - 1][j - 1], j);
                dp[i][j] = pls(f1, f2);
            }
        }
    }
    cout << dp[n][1];
    return 0;
}

• Subtask 1: 0 / 6
• Subtask 2: 0 / 30
• Subtask 3: 0 / 15
• Subtask 4: 0 / 49