CSES - Datatähti 2019 alku - Results
Submission details
Task:Ruudukko
Sender:Olli
Submission time:2018-10-02 17:22:50 +0300
Language:C++
Status:READY
Result:45
Feedback
groupverdictscore
#1ACCEPTED31
#2ACCEPTED14
#30
Test results
testverdicttimegroup
#1ACCEPTED0.02 s1details
#2ACCEPTED0.03 s1details
#3ACCEPTED0.01 s1details
#4ACCEPTED0.01 s1details
#5ACCEPTED0.02 s1details
#6ACCEPTED0.01 s1details
#7ACCEPTED0.02 s1details
#8ACCEPTED0.02 s1details
#9ACCEPTED0.02 s1details
#10ACCEPTED0.02 s1details
#11ACCEPTED0.02 s2details
#12ACCEPTED0.03 s2details
#13ACCEPTED0.02 s2details
#14ACCEPTED0.04 s2details
#15ACCEPTED0.07 s2details
#16ACCEPTED0.10 s2details
#17ACCEPTED0.11 s2details
#18ACCEPTED0.13 s2details
#19ACCEPTED0.12 s2details
#20ACCEPTED0.12 s2details
#210.12 s3details
#220.12 s3details
#230.11 s3details
#24ACCEPTED0.11 s3details
#25ACCEPTED0.11 s3details
#260.13 s3details
#270.11 s3details
#280.12 s3details
#290.12 s3details
#30ACCEPTED0.12 s3details

Code

#include <iostream>
#include <queue>
#include <vector>
using namespace std;
bool printStuff = false;
typedef long long ll;
const int N = 555;
const int M = 1e9 + 7;
char t[N][N];
ll n;
int aA;
int amB;
void swaR(int a, int b) {
for(int x = 1; x <= n; ++x) {
char c = t[a][x];
char d = t[b][x];
t[a][x] = d;
t[b][x] = c;
}
}
void swaC(int a, int b) {
for(int y = 1; y <= n; ++y) {
char c = t[y][a];
char d = t[y][b];
t[y][a] = d;
t[y][b] = c;
}
}
void print() {
for(int y = 1; y <= n; ++y) {
for(int x = 1; x <= n; ++x) {
cout << t[y][x];
}
cout << "\n";
}
cout << "\n";
}
void sor() {
vector<int> broken;
for(int y = n; y >= n - amB + 1; --y) {
bool conB = false;
for(int x = 1; x <= n; ++x) {
if(t[y][x] == 'B') {
conB = true;
break;
}
}
if(!conB) broken.push_back(y);
}
for(int y = n - amB; y >= 1; --y) {
bool conB = false;
for(int x = 1; x <= n; ++x) {
if(t[y][x] == 'B') {
conB = true;
break;
}
}
if(!conB) {
continue;
}
int k = broken[broken.size() - 1];
swaR(k, y);
broken.pop_back();
}
for(int y = n; y >= n - amB + 1; --y) {
int col = -1;
for(int x = 1; x <= n; ++x) {
if(t[y][x] == 'B') {
col = x;
}
}
swaC(n - y + 1, col);
}
aA = 0;
for(int x = amB + 1; x <= n; ++x) {
for(int y = n - amB; y >= 1; --y) {
if(t[y][x] == 'A') {
++aA;
}
}
}
for(int y = n - amB; y >= n - amB - aA + 1; --y) {
bool conA = false;
for(int x = amB + 1; x <= n; ++x) {
if(t[y][x] == 'A') {
conA = true;
break;
}
}
if(!conA) {
broken.push_back(y);
}
}
for(int y = n - amB - aA; y >= 1; --y) {
bool conA = false;
for(int x = amB + 1; x <= n; ++x) {
if(t[y][x] == 'A') {
conA = true;
break;
}
}
if(conA) {
int k = broken[broken.size() - 1];
swaR(k, y);
broken.pop_back();
}
}
for(int y = n - amB; y >= n - amB - aA + 1; --y) {
int col = -1;
for(int x = amB + 1; x <= n; ++x) {
if(t[y][x] == 'A') {
col = x;
break;
}
}
swaC(n - y + 1, col);
}
if(printStuff) {
cout << n << "\n";
print();
}
}
ll dp[N][N];
void fillDP() {
dp[0][0] = 1;
for(int x = 1; x <= n; ++x) {
dp[x][0] = dp[x-1][0]*x;
dp[x][0] %= M;
}
for(ll y = 1; y <= n; ++y) {
for(ll x = y; x <= n; ++x) {
dp[x][y] = dp[x-1][y-1]*(x-y);
dp[x][y] %= M;
if(y == 1) continue;
dp[x][y] += dp[x-1][y-2]*(y-1);
dp[x][y] %= M;
}
}
}
ll exp(ll a, ll e) {
if(e == 0) return 1;
if(e%2 == 0) {
ll c = exp(a, e/2);
return (c*c)%M;
}
ll c = exp(a, e-1);
return (c*a)%M;
}
ll fact[N];
ll binom[N][N];
bool marked[N];
int main() {
cin >> n;
for(int y = 1; y <= n; ++y) {
for(int x = 1; x <= n; ++x) {
char c;
cin >> c;
t[y][x] = c;
if(c == 'B') ++amB;
}
}
sor();
fillDP();
fact[0] = 1;
for(ll i = 1; i <= n; ++i) {
fact[i] = fact[i-1]*i;
fact[i] %= M;
}
for(int m = 0; m <= n; ++m) {
for(int k = 0; k <= m; ++k) {
ll b = fact[m];
b *= exp(fact[k], M-2);
b %= M;
b *= exp(fact[m-k], M-2);
b %= M;
binom[m][k] = b;
}
}
ll ans = 0;
int a1 = 0;
int a2 = 0;
int a3 = 0;
//calculate a2
for(int y = 1; y <= n - amB - aA; ++y) {
for(int x = 1; x <= amB; ++x) {
if(t[y][x] == 'A') {
++a2;
}
}
}
//calculate a3;
for(int y = n - amB; y <= n; ++y) {
for(int x = amB + aA + 1; x <= n; ++x) {
if(t[y][x] == 'A') {
++a3;
}
}
}
//calculate a1;
for(int x = 1; x <= amB; ++x) {
for(int y = n - amB + 1; y <= n; ++y) {
if(t[y][x] == 'A') {
++a1;
}
}
}
/*
for(int i = 0; i <= n; ++i) {
for(int a = 0; a <= i; ++a) {
cout << dp[i][a] << " ";
}
cout << "\n";
}
cout << "\n";
*/
int initialB = 0;
//How many B:s have been hit initially
for(int x = 1; x <= amB; ++x) {
for(int y = 1; y <= n; ++y) {
if(t[y][x] == 'A') {
if(!marked[x]) {
++initialB;
marked[x] = true;
}
if(y >= n - amB + 1) {
if(!marked[n-y+1]) {
++initialB;
marked[n-y+1] = true;
}
}
}
}
}
for(int y = n - amB + 1; y <= n; ++y) {
for(int x = amB + 1; x <= n; ++x) {
if(t[y][x] == 'A') {
if(!marked[n - y + 1]) {
++initialB;
marked[n-y+1] = true;
}
}
}
}
int hitAbove = 0;
int noHitAbove = 0;
int hitRight = 0;
int noHitRight = 0;
for(int x = 1; x <= amB; ++x) {
bool contains = false;
for(int y = 1; y <= n; ++y) {
if(t[y][x] == 'A') {
contains = true;
break;
}
}
if(contains) continue;
for(int y = 1; y <= n; ++y) {
if(t[y][x] == 'B') {
if(marked[x]) {
++noHitAbove;
} else {
++hitAbove;
}
break;
}
}
}
for(int y = n - amB + 1; y <= n; ++y) {
bool contains = false;
for(int x = 1; x <= n; ++x) {
if(t[y][x] == 'A') {
contains = true;
break;
}
}
if(contains) continue;
for(int x = 1; x <= n; ++x) {
if(t[y][x] == 'B') {
if(marked[x]) {
++noHitRight;
} else {
++hitRight;
}
break;
}
}
}
for(ll f2 = max(a2, a3); f2 <= min((ll) amB - a1, n - amB - aA); ++f2) {
for(ll amountOfB = initialB; amountOfB <= amB; ++amountOfB) {
//We will have amountOfB of B:s that have been hit
//We have to hit amountOfB - initialB more
ll A23 = 0;
int t = amountOfB - initialB;
if(t > f2 - a2 + f2 - a3) continue;
int s = n - amB - aA;
if(s < a2 || s < a3) continue;
if(printStuff) {
cout << "\n\n";
cout << "The configuration we have: \n";
cout << "We have to hit " << t << " more B:s\n";
cout << "We should add " << f2 - a2 << " and " << f2 - a3 << " new ones \n";
cout << "There are " << noHitAbove << " and " << noHitRight << " choices that do not hit\n";
cout << "and " << hitAbove << " and " << hitRight << " choices that hit a new one \n";
}
for(int o2 = 0; o2 <= t; ++o2) {
int d2 = f2 - a2;
ll A2 = binom[noHitAbove][d2 - o2]*binom[hitAbove][o2];
A2 %= M;
A2 *= fact[s - a2];
A2 %= M;
A2 *= exp(fact[s - a2 - d2], M-2);
A2 %= M;
int o3 = t - o2;
int d3 = f2 - a3;
if(o3 > d3) continue;
if(hitRight < o2) continue;
ll A3 = binom[hitRight - o2][o3] * binom[noHitRight + o2][d3];
A3 %= M;
A3 *= fact[s - a3];
A3 %= M;
A3 *= exp(fact[s - a3 - d3], M-2);
A3 %= M;
A23 += A2*A3;
if(printStuff) {
cout << "So if " << o2 << " " << o3 << " we have " << A2 << " " << A3 << "\n";
cout << "Because we have " << s - a2 << " and " << s - a3 << " possible depths\n";
cout << "And difference d3 is " << d3 << "\n";
cout << binom[hitRight - o2][o3] << " " << binom[noHitRight + o2][d3] << " " << binom[s-a3][d3] << "\n";
}
A23 %= M;
}
if(printStuff) {
cout << "The result is, we have " << A23 << " choices for the A:s\n";
}
if(A23 == 0) continue;
ll f1 = amB - f2;
ll d1 = f1 - a1;
ll A1 = dp[d1][amB - amountOfB];
if(printStuff) {
cout << "In this case we have " << A1 << " choices for A1\n";
cout << "That's because we added " << d1 << " new A:s to the grid\n";
cout << "and there are " << amB - amountOfB << " B:s in the small area\n";
cout << "The amount of B:s hitted is " << amountOfB << "\n";
}
ll f4 = n - 2*f2 - f1 - aA;
ll A4 = 1;
for(ll i = 1; i <= f4; ++i) {
A4 *= i;
A4 %= M;
}
ll B = dp[n - amB][aA + f4];
ll cur = A23;
cur %= M;
cur *= A1;
cur %= M;
cur *= A4;
cur %= M;
cur *= B;
cur %= M;
if(printStuff) {
cout << "Statistics for " << f2 << " " << amountOfB << "\n";
cout << "Number of ways for A:s " << A1*A23*A4 << "\n";
cout << "Number of ways for A1 is " << A1 << " and for A23 it's " << A23 << " and for A4 " << A4 << "\n";
cout << "Number of ways for B:s " << B << "\n";
cout << "Total number of ways: " << A1*A23*A4*B << "\n";
cout << "\n\n";
}
ans += cur;
ans %= M;
}
}
cout << ans << "\n";
}

Test details

Test 1

Group: 1

Verdict: ACCEPTED

input
2
..
..

correct output
2

user output
2

Test 2

Group: 1

Verdict: ACCEPTED

input
2
..
A.

correct output
1

user output
1

Test 3

Group: 1

Verdict: ACCEPTED

input
2
B.
.A

correct output
0

user output
0

Test 4

Group: 1

Verdict: ACCEPTED

input
3
...
...
...

correct output
12

user output
12

Test 5

Group: 1

Verdict: ACCEPTED

input
4
....
....
....
....

correct output
216

user output
216

Test 6

Group: 1

Verdict: ACCEPTED

input
5
.....
.....
.....
.....
...

correct output
5280

user output
5280

Test 7

Group: 1

Verdict: ACCEPTED

input
5
....A
.....
.....
.....
...

correct output
264

user output
264

Test 8

Group: 1

Verdict: ACCEPTED

input
5
B....
.....
.....
.A.B.
...

correct output
22

user output
22

Test 9

Group: 1

Verdict: ACCEPTED

input
5
B.A..
....A
.....
A.B..
...

correct output
2

user output
2

Test 10

Group: 1

Verdict: ACCEPTED

input
5
A.B..
BA...
.B.A.
...BA
...

correct output
1

user output
1

Test 11

Group: 2

Verdict: ACCEPTED

input
10
..........
..........
..........
..........
...

correct output
306442892

user output
306442892

Test 12

Group: 2

Verdict: ACCEPTED

input
50
.................................

correct output
694861480

user output
694861480

Test 13

Group: 2

Verdict: ACCEPTED

input
111
.................................

correct output
555319110

user output
555319110

Test 14

Group: 2

Verdict: ACCEPTED

input
222
.................................

correct output
108372237

user output
108372237

Test 15

Group: 2

Verdict: ACCEPTED

input
333
.................................

correct output
259107857

user output
259107857

Test 16

Group: 2

Verdict: ACCEPTED

input
444
.................................

correct output
19906314

user output
19906314

Test 17

Group: 2

Verdict: ACCEPTED

input
497
.................................

correct output
224313667

user output
224313667

Test 18

Group: 2

Verdict: ACCEPTED

input
498
.................................

correct output
929574601

user output
929574601

Test 19

Group: 2

Verdict: ACCEPTED

input
499
.................................

correct output
600226043

user output
600226043

Test 20

Group: 2

Verdict: ACCEPTED

input
500
.................................

correct output
198353194

user output
198353194

Test 21

Group: 3

Verdict:

input
499
.................................

correct output
840243733

user output
472998430

Test 22

Group: 3

Verdict:

input
499
........................A........

correct output
4146290

user output
339256637

Test 23

Group: 3

Verdict:

input
499
B.........A......................

correct output
173518884

user output
805863113

Test 24

Group: 3

Verdict: ACCEPTED

input
499
...A....B........................

correct output
20044800

user output
20044800

Test 25

Group: 3

Verdict: ACCEPTED

input
499
AB...............................

correct output
2

user output
2

Test 26

Group: 3

Verdict:

input
500
.................................

correct output
121064146

user output
453728449

Test 27

Group: 3

Verdict:

input
500
.................................

correct output
848435259

user output
631716298

Test 28

Group: 3

Verdict:

input
500
.....B........A..................

correct output
296240911

user output
925231462

Test 29

Group: 3

Verdict:

input
500
.A......B........................

correct output
2196

user output
3060

Test 30

Group: 3

Verdict: ACCEPTED

input
500
...AB............................

correct output
1

user output
1