Revisions to Implement the divisibility-by-7 rule

added 11 characters in body

Source Link

edited Feb 14, 2016 at 20:42

1.7k
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25

JavaScript ES6, 38 bytesJavaScript ES6, 38 bytes

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i

Fails with 36893488147419103232 and using ~~(1/10) will also fail for 700168844221

Test:

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

JavaScript ES6, 38 bytes

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i

Fails with 36893488147419103232 and using ~~(1/10) will also fail for 700168844221

Test:

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

JavaScript ES6, 38 bytes

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i

Fails with 36893488147419103232 and using ~~(1/10) will also fail for 700168844221

Test:

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

added 16 characters in body

Source Link

edited Feb 14, 2016 at 20:34

Andreas Louv

1.7k
13
25

JavaScript ES6, 30 bytesJavaScript ES6, 38 bytes

a=i=>i>70?a(~~Math.floor(i/10)-i%10*2):i

Fails with 36893488147419103232 and using ~~(1/10) will also fail for 700168844221

Test:

a=i=>i>70?a(~~Math.floor(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

JavaScript ES6, 30 bytes

a=i=>i>70?a(~~(i/10)-i%10*2):i

Test:

a=i=>i>70?a(~~(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

JavaScript ES6, 38 bytes

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i

Fails with 36893488147419103232 and using ~~(1/10) will also fail for 700168844221

Test:

a=i=>i>70?a(Math.floor(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

added 11 characters in body

Source Link

edited Feb 14, 2016 at 20:31

Andreas Louv

1.7k
13
25

JavaScript ES6, 30 bytesJavaScript ES6, 30 bytes

a=i=>i>70?a(~~(i/10)-i%10*2):i

Test:

a=i=>i>70?a(~~(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

JavaScript ES6, 30 bytes

a=i=>i>70?a(~~(i/10)-i%10*2):i

Test:

a=i=>i>70?a(~~(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

JavaScript ES6, 30 bytes

a=i=>i>70?a(~~(i/10)-i%10*2):i

Test:

a=i=>i>70?a(~~(i/10)-i%10*2):i
O.textContent = O.textContent.replace(/(-?\d+) +(-?\d+)/g, (_,i,o) =>
  _+": "+(a(+i)==o?"OK":"Fail")
);

<pre id=O>1                       1
10                      10
100                     10
13                      13
42                      42
2016                    0
9                       9
99                      -9
9999                    -3
12345                   3
700168844221            70
36893488147419103232    32</pre>

added 690 characters in body

Source Link

edited Feb 14, 2016 at 20:24

Andreas Louv

1.7k
13
25

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Source Link

created Feb 14, 2016 at 20:16

Andreas Louv

1.7k
13
25

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JavaScript ES6, 38 bytesJavaScript ES6, 38 bytes

JavaScript ES6, 38 bytes

JavaScript ES6, 38 bytes

JavaScript ES6, 30 bytesJavaScript ES6, 38 bytes

JavaScript ES6, 30 bytes

JavaScript ES6, 38 bytes

JavaScript ES6, 30 bytesJavaScript ES6, 30 bytes

JavaScript ES6, 30 bytes

JavaScript ES6, 30 bytes