Submission #405362

#	Time	Username	Problem	Language	Result	Execution time	Memory
405362		my99n	K-th path (IZhO11_kthpath)	C++14	0 / 100	1 ms	204 KiB

kthpath

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

char a[35][35];
string answer;
long double f[65];
long double n, m, k; 

long double fact (int a) {
  if (a <= 1) return 1;
  if (f[a]) return f[a];
  return f[a] = a * fact(a-1);
}

long double ways (int i, int j) {
  return ( fact(n-i+m-j) / fact(m-j) ) / fact(n-i);
}

void ans (int i = 1, int j = 1) {
  if (i == n) {
    for (int x = j; x <= m; x++) answer += a[i][x];
    return;
  }
  if (j == m) {
    for (int x = i; x <= n; x++) answer += a[x][j];
    return;
  }
  // cerr << ways(i+1, j) << ' ' << ways(i, j+1) << ' ' << k << endl;
  answer += a[i][j];
  if (a[i+1][j] < a[i][j+1]) {
    if (ways(i+1, j) >= k) return ans(i+1, j);
    k-=ways(i+1, j);
    return ans(i, j+1);
  }
  else {
    if (ways(i, j+1) >= k) return ans(i, j+1);
    k-=ways(i, j+1);
    return ans (i+1, j);
  }
}

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      cin >> a[i][j];
    }
  }
  cin >> k;
  ans(); cout << answer;
  return 0;
}
/* POSSIBLE BUGS
  overflow
*/
/* TESTCASE

*/

• Subtask 1: 0 / 100