Submission #118221

#	Time	Username	Problem	Language	Result	Execution time	Memory
118221		sebinkim	Solitaire (JOI16_solitaire)	C++14	100 / 100	142 ms	35044 KiB

solitaire

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
 
const ll mod = 1e9 + 7;
 
char A[2020], B[2020], C[2020];
ll dp[2020][6060], S[2020];
ll X1[6060], X2[6060], X3[6060], Y[6060];
ll n, ans;

void die() { printf("0\n"); exit(0); }
 
int main()
{
	ll i, j, k, x, s, s1, s2, t1, t2;
	ll l1, l2, y;
 
	scanf("%lld%s%s%s", &n, A + 1, B + 1, C + 1);
 
	if(A[1] == 'x' || A[n] == 'x') die();
	if(C[1] == 'x' || C[n] == 'x') die();
 
	for(i=1; i<n; i++){
		if(A[i] == 'x' && A[i + 1] == 'x') die();
		if(C[i] == 'x' && C[i + 1] == 'x') die();
	}
 
	dp[0][0] = 1;
 
	for(i=1; i<=n; i++){
		S[i] = S[i - 1] + (A[i] == 'x') + (B[i] == 'x') + (C[i] == 'x');
		s = S[i];
 
		if(B[i] == 'o'){
			if(A[i] == 'x' && C[i] == 'x') t1 = 0;
			else if(A[i] == 'x' || C[i] == 'x') t1 = 1;
			else t1 = 2;
 
			for(k=0; k<=s; k++){
				if(t1 == 0) dp[i][0] = (dp[i][0] + dp[i - 1][k] * s * (s - 1)) % mod;
				else if(t1 == 1) dp[i][0] = (dp[i][0] + dp[i - 1][k] * s) % mod;
				else dp[i][0] = (dp[i][0] + dp[i - 1][k]) % mod;
			}
 
			if(B[i - 1] == 'o' || i < 3) continue;
 
			s2 = S[i - 2];
			if(A[i - 1] == 'x' && C[i - 1] == 'x') t2 = 0;
			else if(A[i - 1] == 'x' || C[i - 1] == 'x') t2 = 1;
			else t2 = 2;
 
			for(k=0; k<=s; k++){
				if(t2 == 0){
					x = k * (s2 - k + 2) * (s2 - k + 1) / 2 * 2 % mod;
					x = (x + (s2 - k + 3) * (s2 - k + 2) * (s2 - k + 1) / 6 * 4) % mod;
				}
				else if(t2 == 1) x = (s2 - k + 2) * (s2 - k + 1) / 2 % mod;
				else x = 0;
 
				x = x * dp[i - 2][k] % mod;
 
				if(t1 == 0) dp[i][0] = (dp[i][0] + x * s * (s - 1)) % mod;
				else if(t1 == 1) dp[i][0] = (dp[i][0] + x * s) % mod;
				else dp[i][0] = (dp[i][0] + x) % mod;
			}
		}
		else{
			if(A[i] == 'x' && C[i] == 'x') t1 = 0;
			else if(A[i] == 'x' || C[i] == 'x') t1 = 1;
			else t1 = 2;
 
			y = 0;
			for(k=0; k<=s; k++){
				y = (y + dp[i - 1][k]) % mod;
			}
 
			for(j=1; j<=s; j++){
				if(t1 == 0) dp[i][j] = (dp[i][j] + y * (j - 1) * (j - 2)) % mod;
				else if(t1 == 1) dp[i][j] = (dp[i][j] + y * (j - 1)) % mod;
				else dp[i][j] = (dp[i][j] + y) % mod;
			}
 
			if(B[i - 1] == 'o' || i < 3) continue;
 
			s2 = S[i - 2];
			s1 = s2 + S[i] - S[i - 1];
			if(A[i - 1] == 'x' && C[i - 1] == 'x') t2 = 0;
			else if(A[i - 1] == 'x' || C[i - 1] == 'x') t2 = 1;
			else t2 = 2;
 
			X1[s + 1] = X2[s + 1] = X3[s + 1] = 0;
			for(k=s; k>=0; k--){
				X1[k] = (X1[k + 1] + dp[i - 2][k] * ((s1 - k + t1) * (s1 - k + t1 - 1) * (s1 - k + t1 - 2) / 6 * 4 % mod)) % mod;
				X2[k] = (X2[k + 1] + dp[i - 2][k] * ((k + 3 - t1) * (s1 - k + t1 - 1) * (s1 - k + t1 - 2) % mod)) % mod;
				X3[k] = (X3[k + 1] + dp[i - 2][k] * (s1 - k + t1 - 1) * (s1 - k + t1 - 2) / 2) % mod;
			}
 
			Y[0] = dp[i - 2][0];
			for(k=1; k<=s; k++){
				Y[k] = (Y[k - 1] + dp[i - 2][k]) % mod;
			}
			
			for(j=1; j<=s; j++){
				if(t1 == 0) x = (j - 1) * (j - 2) % mod;
				else if(t1 == 1) x = (j - 1) % mod;
				else x = 1;
				
				l1 = max(j + t1 - 2, 0ll);
				l2 = max(l1 - 1, 0ll);
 
				if(t2 == 0){
					dp[i][j] = (dp[i][j] + x * X1[l1]) % mod;
					dp[i][j] = (dp[i][j] + x * X2[l1] - j * x % mod * X3[l1] * 2 % mod + mod) % mod;
					dp[i][j + 1] = (dp[i][j + 1] + x * j % mod * X3[l1] * 2) % mod;
					
					dp[i][j] = (dp[i][j] + x * Y[l2] % mod * ((s1 - j + 3) * (s1 - j + 2) * (s1 - j + 1) / 6 * 4 % mod)) % mod;
					dp[i][j + 1] = (dp[i][j + 1] + x * Y[l2] % mod * (j * (s1 - j + 2) * (s1 - j + 1) % mod)) % mod;
				}
				else if(t2 == 1){
					dp[i][j] = (dp[i][j] + x * X3[l1]) % mod;
 
					dp[i][j] = (dp[i][j] + x * Y[l2] % mod * (s1 - j + 2) * (s1 - j + 1) / 2) % mod;
				}
			}
 
			dp[i][s + 1] = 0;
		}
	}
 
	s = S[n];
 
	for(i=0; i<=s; i++){
		ans = (ans + dp[n][i]) % mod;
	}
 
	printf("%lld\n", ans);
 
	return 0;
}

Compilation message (stderr)

solitaire.cpp: In function 'int main()':
solitaire.cpp:21:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld%s%s%s", &n, A + 1, B + 1, C + 1);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 20 / 20
• Subtask 4: 38 / 38
• Subtask 5: 20 / 20