# 973. K Closest Points to Origin

We have a list of `points` on the plane.  Find the `K` closest points to the origin `(0, 0)`.

(Here, the distance between two points on a plane is the Euclidean distance.)

You may return the answer in any order.  The answer is guaranteed to be unique (except for the order that it is in.)

Example 1:

Input:

```points = [[1,3],[-2,2]], K = 1
```

Output:

```[[-2,2]]
```

Explanation:

```The distance between (1, 3) and the origin is sqrt(10).
The distance between (-2, 2) and the origin is sqrt(8).
Since sqrt(8) < sqrt(10), (-2, 2) is closer to the origin.
We only want the closest K = 1 points from the origin, so the answer is just [[-2,2]].
```

Example 2:

Input:

```points = [[3,3],[5,-1],[-2,4]], K = 2
```

Output:

```[[3,3],[-2,4]]
(The answer [[-2,4],[3,3]] would also be accepted.)
```

Note:

1. `1 <= K <= points.length <= 10000`
2. `-10000 < points[i][0] < 10000`
3. `-10000 < points[i][1] < 10000`
A acceptable but definitely no the best solution….
In PHP:
1. a ** b means power (a,b)
2.  <=>, the spaceship operator,  used by ‘comparator’
1. if left < right return -1
2. if left > right return 1
3. if left == right return 0
```class Solution {

/**
* @param Integer[][] \$points
* @param Integer \$K
* @return Integer[][]
*/
function kClosest(\$points, \$K) {
usort(\$points, function (\$a, \$b){
return (\$a[0]**2 + \$a[1]**2) <=> (\$b[0]**2 + \$b[1]**2);
});

\$result = [];
\$i = 0;
foreach(\$points as \$p){
if(\$i >= \$K){
break;
}
\$result[] = \$p;
\$i ++;

}
return \$result;
}
}```