#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,fma")
//#pragma GCC optimization ("unroll-loops")
#define rep(i, x, y) for(int i = x; i <= y; ++i)
#define repi(i,x,y) for(int i = x; i >= y; --i)
#define ci(x) int x; cin>> x
#define TC(t) ci(t); while(t--)
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define cii(x, y) ci(x); ci(y)
#define ciii(x, y, z) ci(x); ci(y); ci(z)
#define mp make_pair
//#define int long long
typedef long long ll;
typedef vector<int> vi;
const int N = 2e3 + 5;
const int NN = 16 + 15;
const int mod = 998244353;
const int mod1 = 1e9 + 9;
const int pi = 31;
const int inf = 1e9 + 6;
const int block = 500;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};
void readfile(){
#ifdef ONLINE_JUDGE
#else
freopen("text.inp", "r", stdin);
#endif // ONLINE_JUDGE
// freopen("connect.in", "r", stdin);
// freopen("connect.out", "w", stdout);
}
int n, s, t;
void inp(){
cin >> n >> s >> t;
}
int dp[N][N];
int add(int x, int y){
x += y;
while(x >= mod) x -= mod;
while(x < 0) x += mod;
return x;
}
int mul(int x, int y){
return (x * 1LL * y) % mod;
}
void process(){
dp[0][0] = 1;
for(int i = 0; i < n; ++i){
for(int j = 0; j <= i; ++j){
if(i+1==s || i+1==t){
dp[i+1][j] = add(dp[i+1][j], dp[i][j]); // add vo component dau tien
dp[i+1][j+1] = add(dp[i+1][j+1], dp[i][j]); // tao mot component moi ben trai cung
}
else{
if(i + 1 < s && i + 1 < t){
dp[i+1][j+1] = add(dp[i+1][j+1], mul(dp[i][j], j + 1)); // tao mot component moi, co j + 1 vi tri
if(j) dp[i+1][j-1] = add(dp[i+1][j-1], mul(dp[i][j], j-1)); // co j - 1 vi tri de merge
}
else if((i + 1 >= t && i + 1 < s) || (i + 1 >= s && i + 1 < t)){
dp[i+1][j+1] = add(dp[i+1][j+1], mul(dp[i][j], j)); // tao mot component moi khong duoc o ben trai cung || phai cung, co j vi tri
if(j) dp[i+1][j-1] = add(dp[i+1][j-1], mul(dp[i][j], j-1)); // co j - 1 vi tri de merge
}
else{
dp[i+1][j+1] = add(dp[i+1][j+1], mul(dp[i][j], j-1)); // tao mot component moi khong duoc o ben trai cung && phai cung, co j - 1 vi tri
if(j) dp[i+1][j-1] = add(dp[i+1][j-1], mul(dp[i][j], j-1)); // co j - 1 vi tri de merge
}
}
}
}
cout << dp[n][1];
}
int main() {
// readfile();
ios_base::sync_with_stdio(0);
cin.tie(0);
// TC(t){
inp();
process();
// reset();
// }
return 0;
}
Compilation message
kangaroo.cpp: In function 'void readfile()':
kangaroo.cpp:34:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
34 | freopen("text.inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
