Ruudukko

#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  string t[n];
  for (int i = 0; i < n; ++i) cin >> t[i];
  bool dp[n][n];
  for (int i = 0; i < n; ++i) dp[n-1][i] = 0, dp[i][n-1] = 1;
  for (int i = n-2; i >= 0; --i) {
    for (int j = n-2; j >= 0; --j) {
      int ai = i+1, aj = j, bi = i, bj = j+1;
      dp[i][j] = 0;
      while (ai != n-1 || aj != n-1) {
        if (t[ai][aj] != t[bi][bj]) {
          dp[i][j] = t[ai][aj] < t[bi][bj];
          break;
        }
        if (dp[ai][aj]) ai++;
        else aj++;
        if (dp[bi][bj]) bi++;
        else bj++;
      }
    }
  }
  int i = 0, j = 0;
  while (i != n-1 || j != n-1) {
    cout << t[i][j];
    if (dp[i][j]) i++;
    else j++;
  }
  cout << t[i][j] << endl;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED