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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#143039#6410. Classical DP Problemtraining4usacoWA 12ms199464kbC++171.5kb2023-08-20 13:35:362023-08-20 13:35:40

Judging History

你现在查看的是最新测评结果

  • [2023-08-20 13:35:40]
  • 评测
  • 测评结果:WA
  • 用时:12ms
  • 内存:199464kb
  • [2023-08-20 13:35:36]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;

#define int long long
const int MAXN = 5e3 + 5;
const int MOD = 998244353;

int n, k;
int a[MAXN], b[MAXN];
int dp[MAXN][MAXN];
int fact[MAXN];

signed main() {
	cin.tie(0)->sync_with_stdio(false);
	
	fact[0] = 1;
	for(int i = 1; i < MAXN; ++i) {
	    fact[i] = fact[i - 1] * i; fact[i] %= MOD;
	}

	cin >> n;
	for(int i = 1; i <= n; ++i) cin >> a[i];
	reverse(a + 1, a + 1 + n);

	int idx = 0, val = n;
	for(int i = n; i >= 2; --i) {
		if(a[i - 1] > a[i]) {
			for(int j = idx + 1; j <= a[i]; ++j) b[j] = val;
			idx = a[i]; val = i - 1;
		}
	}
	for(int i = idx + 1; i <= a[1]; ++i) b[i] = val;
	
	for(int i = 1; i <= n; ++i) {
	    if(i <= a[i]) k = i;
	    else break;
	}
	
	dp[0][0] = 1;
	for(int i = 0; i < k; ++i) {
	    for(int j = 0; j <= a[k + 1]; ++j) {
	        dp[i + 1][j] += ((a[i + 1] - (a[k + 1] - j)) % MOD * dp[i][j]) % MOD; dp[i + 1][j] %= MOD;
	        dp[i + 1][j + 1] += ((a[k + 1] - j) * dp[i][j]) % MOD; dp[i + 1][j + 1] %= MOD;
	    }
	}
	
	int ans = dp[k][a[k + 1]] % MOD;
	
	memset(dp, 0, sizeof(dp));
	dp[0][0] = 1; swap(a, b);
	for(int i = 0; i < k; ++i) {
	    for(int j = 0; j <= a[k + 1]; ++j) {
	        dp[i + 1][j] += ((a[i + 1] - (a[k + 1] - j)) % MOD * dp[i][j]) % MOD; dp[i + 1][j] %= MOD;
	        dp[i + 1][j + 1] += ((a[k + 1] - j) * dp[i][j]) % MOD; dp[i + 1][j + 1] %= MOD;
	    }
	}
	
	ans += dp[k][a[k + 1]] % MOD; ans %= MOD;
	ans -= fact[k]; ans %= MOD;
	cout << k << " " << ans << endl;
}

详细

Test #1:

score: 100
Accepted
time: 11ms
memory: 199200kb

input:

3
1 2 3

output:

2 6

result:

ok 2 number(s): "2 6"

Test #2:

score: 0
Accepted
time: 0ms
memory: 199248kb

input:

1
1

output:

1 1

result:

ok 2 number(s): "1 1"

Test #3:

score: 0
Accepted
time: 4ms
memory: 199304kb

input:

2
1 1

output:

1 2

result:

ok 2 number(s): "1 2"

Test #4:

score: 0
Accepted
time: 8ms
memory: 199248kb

input:

2
2 2

output:

2 6

result:

ok 2 number(s): "2 6"

Test #5:

score: 0
Accepted
time: 3ms
memory: 199456kb

input:

3
1 1 1

output:

1 3

result:

ok 2 number(s): "1 3"

Test #6:

score: 0
Accepted
time: 0ms
memory: 199288kb

input:

3
2 2 2

output:

2 9

result:

ok 2 number(s): "2 9"

Test #7:

score: 0
Accepted
time: 1ms
memory: 199308kb

input:

3
3 3 3

output:

3 48

result:

ok 2 number(s): "3 48"

Test #8:

score: 0
Accepted
time: 1ms
memory: 199464kb

input:

5
1 1 3 3 4

output:

3 47

result:

ok 2 number(s): "3 47"

Test #9:

score: 0
Accepted
time: 8ms
memory: 199308kb

input:

10
2 4 5 5 5 5 6 8 8 10

output:

5 864

result:

ok 2 number(s): "5 864"

Test #10:

score: -100
Wrong Answer
time: 12ms
memory: 199200kb

input:

30
6 8 9 9 9 10 13 14 15 15 16 17 17 18 20 22 22 23 23 24 24 25 25 25 27 28 28 29 29 30

output:

17 -12054489

result:

wrong answer 2nd numbers differ - expected: '986189864', found: '-12054489'