UVa 12027 - Very Big Perfect Squares

Accepted date: 2015-09-25
Ranking (as of 2015-09-25): 8 out of 228
Language: C++

/*
  UVa 12027 - Very Big Perfect Squares

  To build using Visual Studio 2012:
    cl -EHsc -O2 UVa_12027_Very_Big_Perfect_Squares.cpp
*/

#include <cstdio>
#include <cstring>
#include <cmath>

int main()
{
  const int sqrts[] = {
    0,
    1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4,
    4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6,
    6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
    7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9
  };
  while (true) {
    const int nr_digits_max = 1001;
    char N[nr_digits_max + 1], A[nr_digits_max + 1];
    scanf("%s", N);
    if (N[0] == '0')
      break;
    int nr_digits = strlen(N), nr_zeros = (nr_digits - 1) / 2, n = N[0] - '0';
    if (!(nr_digits & 1)) {
      n *= 10;
      n += N[1] - '0';
    }
    A[0] = sqrts[n] + '0';
    memset(A + 1, '0', nr_zeros);
    A[nr_zeros + 1] = '\0';
    puts(A);
  }
  return 0;
}