#include "bits/stdc++.h"
#define ll long long
using namespace std;
const int sz = 33;
char s[sz + sz];
char a[sz][sz];
int vi[sz][sz][2];
ll dp[sz][sz][2];
int n, m;
ll go(int i, int j, bool f) {
if (i >= n || j >= m) return 0ll;
if (f && a[i][j] > s[i + j]) return 0ll;
if (n - 1 == i && m - 1 == j) return 1ll;
if (a[i][j] < s[i + j]) f = 0;
int& v = vi[i][j][f];
ll& r = dp[i][j][f];
if (v ++) return r;
r += go(i + 1, j, f);
r += go(i, j + 1, f);
return r;
}
void zero() {
for (int i = 0; i < n; i ++)
for (int j = 0; j < m; j ++)
for (int k : {0, 1})
dp[i][j][k] = vi[i][j][k] = 0;
}
int main() {
cin >> n >> m;
for (int i = 0; i < n; i ++)
for (int j = 0; j < m; j ++)
cin >> a[i][j];
ll k;
cin >> k;
for (int i = 0; i < n + m; i ++)
s[i] = 'z';
/*
s[0] = 'a', s[1] = 'b', s[2] = 'f', s[3] = 'd', s[4] = 'g';
cout << "init: " << go(0, 0, 1) << '\n';
for (int i = 0; i < n; i ++) {
for (int j = 0; j < m; j ++)
cout << dp[i][j] << ' ';
cout << '\n';
}
*/
for (int i = 0; i < n + m - 1; i ++) {
char lo = 'a', hi = 'z';
while (lo != hi) {
char mi = (lo + hi) / 2;
s[i] = mi;
zero();
//cout << i << ' ' << mi << ' ' << go(0, 0, 1) << ' ' << k << '\n';
if (go(0, 0, 1) >= k)
hi = mi;
else lo = mi + 1;
}
s[i] = lo;
//cout << "fn: " << i << ' ' << s[i] << '\n';
}
for (int i = 0; i < n + m - 1; i ++)
cout << s[i];
cout << '\n';
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
600 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
1 ms |
348 KB |
Output is correct |
7 |
Correct |
1 ms |
600 KB |
Output is correct |
8 |
Correct |
1 ms |
348 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
1 ms |
348 KB |
Output is correct |
11 |
Correct |
0 ms |
348 KB |
Output is correct |
12 |
Correct |
1 ms |
344 KB |
Output is correct |
13 |
Correct |
2 ms |
348 KB |
Output is correct |
14 |
Correct |
2 ms |
348 KB |
Output is correct |
15 |
Correct |
2 ms |
468 KB |
Output is correct |
16 |
Correct |
3 ms |
348 KB |
Output is correct |
17 |
Correct |
3 ms |
348 KB |
Output is correct |
18 |
Correct |
4 ms |
348 KB |
Output is correct |
19 |
Correct |
3 ms |
348 KB |
Output is correct |
20 |
Correct |
3 ms |
348 KB |
Output is correct |