php:

function threeSum(array $nums): array

{

$result = [];

$length = count($nums);

if ($length < 3) {

return [];

}

sort($nums);

for ($i = 0; $i < $length; $i++) {

// 如果大于0结束

if ($nums[$i] > 0) break;

// 去重

if ($i > 0 && $nums[$i] == $nums[$i - 1]) continue;

$left = $i + 1;

$right = $length - 1;

// 比较

while ($left < $right) {

$sum = $nums[$i] + $nums[$left] + $nums[$right];

if ($sum < 0) {

$left++;

} elseif ($sum > 0) {

$right--;

} else {

array_push($result, [$nums[$i], $nums[$left], $nums[$right]]);

while ($left < $right && $nums[$left] == $nums[$left + 1]) $left++;

while ($left < $right && $nums[$right - 1] == $nums[$right]) $right--;

$left++;

$right--;

}

}

}

return $result;

}

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