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| 1 | +/** |
| 2 | + * Definition for a point. |
| 3 | + * class Point( |
| 4 | + * public $x = 0; |
| 5 | + * public $y = 0; |
| 6 | + * function __construct(int $x = 0, int $y = 0) { |
| 7 | + * $this->x = $x; |
| 8 | + * $this->y = $y; |
| 9 | + * } |
| 10 | + * ) |
| 11 | + */ |
| 12 | +class Solution { |
| 13 | + |
| 14 | + /** |
| 15 | + * @param Point[] $points |
| 16 | + * @return Integer |
| 17 | + */ |
| 18 | + function maxPoints($points) { |
| 19 | + $max = 0; |
| 20 | + $duplicated = 0; |
| 21 | + $isMaxChanged = false; |
| 22 | + if ($points == null || count($points) == 0) { |
| 23 | + return 0; |
| 24 | + } else if (count($points) == 1) { |
| 25 | + return 1; |
| 26 | + } else if (count($points) == 2) { |
| 27 | + return 2; |
| 28 | + } else { |
| 29 | + for ($i=0;$i<count($points);$i++) { |
| 30 | + //key is a string = y + "/" + x to prevent from division/float/double/BigDecimal |
| 31 | + //value is amount of points on the same line -1 |
| 32 | + $amount = []; |
| 33 | + //j=i+1 to prevent from backwarding loop |
| 34 | + for ($j=$i+1;$j<count($points);$j++) { |
| 35 | + $y = $points[$j]->y - $points[$i]->y; |
| 36 | + $x = $points[$j]->x - $points[$i]->x; |
| 37 | + |
| 38 | + if ($x == 0 && $y == 0) { |
| 39 | + $duplicated++; |
| 40 | + if ($isMaxChanged == true) { |
| 41 | + $max++; |
| 42 | + } else if ($max < $duplicated) { |
| 43 | + $max = $duplicated; |
| 44 | + } |
| 45 | + |
| 46 | + } else { |
| 47 | + $gcd = self::getGCD($y,$x); |
| 48 | + if ($gcd != 0) { |
| 49 | + $y = intval($y / $gcd); |
| 50 | + $x = intval($x / $gcd); |
| 51 | + $k = $y."/".$x; |
| 52 | + if (array_key_exists($k, $amount)) { |
| 53 | + $n = $amount[$k]; |
| 54 | + $amount[$k] = $n+1; |
| 55 | + if ($max < $n+1+$duplicated) { |
| 56 | + $max = $n+1+$duplicated; |
| 57 | + $isMaxChanged = true; |
| 58 | + } |
| 59 | + } else { |
| 60 | + $amount[$k] = 1; |
| 61 | + if ($max < 1+$duplicated) { |
| 62 | + $max = 1+$duplicated; |
| 63 | + $isMaxChanged = true; |
| 64 | + } |
| 65 | + } |
| 66 | + } |
| 67 | + } |
| 68 | + } |
| 69 | + |
| 70 | + $duplicated = 0; |
| 71 | + $isMaxChanged = false; |
| 72 | + |
| 73 | + } |
| 74 | + return $max+1; |
| 75 | + } |
| 76 | + } |
| 77 | + |
| 78 | + //horizontal lines make x=0 & y=1 |
| 79 | + //vertical lines make x=1 & y=0 |
| 80 | + //same position points should not invoke this function whick make x=0 & y=0 |
| 81 | + //other points return the gcd |
| 82 | + function getGCD($y, $x) { |
| 83 | + if ($x == 0) { |
| 84 | + if ($y == 0) { |
| 85 | + return 0;//same point |
| 86 | + } else { |
| 87 | + return $y;//horizontal lines |
| 88 | + } |
| 89 | + } else { |
| 90 | + //normal case and the vertical lines |
| 91 | + if ($y%$x != 0) { |
| 92 | + return self::getGCD($x,$y%$x); |
| 93 | + } else { |
| 94 | + return $x; |
| 95 | + } |
| 96 | + } |
| 97 | + } |
| 98 | +} |
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