1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 300;
ll dp[N][N];
int a, b;
ll k;
string find_kth(int a, int b, ll k){
if (a == 0) {
return string(b, 'b');
}
if (b == 0) {
return string(a, 'a');
}
if (k <= dp[a - 1][b]) {
return string("a") + find_kth(a - 1, b, k);
}
else {
return string("b") + find_kth(a, b-1, k - dp[a - 1][b]);
}
}
int main(){
cin >> a >> b >> k;
dp[0][0] = 1;
for (int i = 0; i <= a; i++) {
for (int j = 0; j <= b; j++) {
if (i > 0) {
dp[i][j] += dp[i - 1][j];
}
if (j > 0) {
dp[i][j] += dp[i][j - 1];
}
}
}
cout << find_kth(a, b, k) << endl;
return 0;
}
|
