PHP算法之最接近的三数之和

<?php
function threeSumClosest($nums, $target) {
    
        sort($nums);
        $count = count($nums);
        $ans = $nums[0] + $nums[1] + $nums[2];
	
        for( $i=0;$i<$count;$i++) {
    
            $start = $i+1; $end = $count - 1;
			
            while($start < $end) {
    
                $sum = $nums[$start] + $nums[$end] + $nums[$i];
                if(abs($target - $sum) < abs($target - $ans)){
    
					$ans = $sum;
				}   
                if($sum > $target){
    
				 	$end--;
				}
                else if($sum < $target){
    
					$start++;
				}  
                else{
    
				 	return $ans;
				}
            }
        }
        return $ans;        
    }

var_dump(threeSumClosest(array(-1,2,1,-4,0),1));
?>