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day-60.cpp
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day-60.cpp
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/*
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.)
*/
// Easy problem: learnt this short and fast way to solve this problem
class Solution {
struct Comp {
bool operator()(vector<int>& a, vector<int>& b) {
return a[1] * a[1] + a[0] * a[0] < b[1] * b[1] + b[0] * b[0];
}
};
public:
vector<vector<int>> kClosest(vector<vector<int>>& points, int K) {
if (K == points.size()) return points;
sort(points.begin(), points.end(), Comp());
return vector<vector<int>>(points.begin(), points.begin() + K);
}
};