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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#103618 | #6346. Record Parity | wnmrmr# | WA | 2ms | 3428kb | C++23 | 1.8kb | 2023-05-07 04:44:05 | 2023-05-07 04:44:06 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
#define all(v) v.begin(), v.end()
#define pb push_back
void dbg_out() { cerr << endl; }
template<typename H, typename... T>
void dbg_out(H h, T... t) { cerr << ' ' << h; dbg_out(t...); }
#define dbg(...) { cerr << #__VA_ARGS__ << ':'; dbg_out(__VA_ARGS__); }
template<int MOD>
struct mint {
int x;
mint(): x(0) {}
mint(int y): x(y<0?y%MOD+MOD : y%MOD) {}
void operator+=(mint rhs) { x += rhs.x; if(x>=MOD) x-= MOD; }
void operator-=(mint rhs) { x -= rhs.x; if(x<0) x+= MOD; }
void operator*=(mint rhs) { x *= rhs.x; x %= MOD; }
void operator/=(mint rhs) { *this *= rhs.inv(); }
mint operator+(mint rhs) { mint res = *this; res += rhs; return res; }
mint operator-(mint rhs) { mint res = *this; res -= rhs; return res; }
mint operator*(mint rhs) { mint res = *this; res *= rhs; return res; }
mint operator/(mint rhs) { mint res = *this; res /= rhs; return res; }
mint inv() { assert(x != 0); return this->pow(MOD-2); }
mint pow(int e) {
mint res = 1;
for(mint p=*this;e>0;e/=2,p*=p) if(e%2)
res *= p;
return res;
}
};
using Z = mint<998244353>;
void solve() {
int n, k; cin >> n >> k;
vector<int> a (n);
for (auto &u : a) cin >> u;
vector<Z> fat (n + 1);
fat[0] = 1;
for (int i = 1; i <= n; i++) fat[i] = fat[i - 1] * i;
auto comb = [&] (int x, int y) {
if (y > x) return Z(0);
return fat[x] / fat[y] / fat[x - y];
};
Z ans = 0;
int cur = 1;
for (int i = 1; i < n; i++) {
if (a[i] < a[i - 1]) {
ans += comb (cur, k);
cur = 1;
}
else cur++;
}
ans += comb (cur, k);
cout << (ans * (k & 1 ? -1 : 1)).x << "\n";
}
signed main() {
ios::sync_with_stdio(false); cin.tie(0);
solve();
}
Details
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Test #1:
score: 100
Accepted
time: 2ms
memory: 3428kb
input:
5 2 4 1 2 5 3
output:
3
result:
ok 1 number(s): "3"
Test #2:
score: 0
Accepted
time: 2ms
memory: 3352kb
input:
7 3 1 2 3 4 5 6 7
output:
998244318
result:
ok 1 number(s): "998244318"
Test #3:
score: 0
Accepted
time: 2ms
memory: 3424kb
input:
5 5 2 5 4 1 3
output:
0
result:
ok 1 number(s): "0"
Test #4:
score: -100
Wrong Answer
time: 2ms
memory: 3420kb
input:
10 3 9 7 3 6 10 4 8 2 5 1
output:
998244352
result:
wrong answer 1st numbers differ - expected: '0', found: '998244352'