# Minimum number of points to be removed to get remaining points on one side of axis

We are given n points in a Cartesian plane. Our task is to find the minimum number of points that should be removed in order to get the remaining points on one side of any axis.

Examples :

```Input : 4
1 1
2 2
-1 -1
-2 2
Output : 1
Explanation :
If we remove (-1, -1) then all the remaining
points are above x-axis. Thus the answer is 1.

Input : 3
1 10
2 3
4 11
Output : 0
Explanation :
All points are already above X-axis. Hence the
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach :
This problem is a simple example of constructive brute force algorithm on Geometry. The solution can be approached simply by finding the number of points on all sides of the X-axis and Y-axis. The minimum of this will be the answer.

 `// CPP program to find minimum points to be moved ` `// so that all points are on same side. ` `#include ` `using` `namespace` `std; ` `typedef` `long` `long` `ll; ` ` `  `// Structure to store the coordinates of a point. ` `struct` `Point  ` `{ ` `    ``int` `x, y; ` `}; ` ` `  `// Function to find the minimum number of points ` `int` `findmin(Point p[], ``int` `n) ` `{ ` `    ``int` `a = 0, b = 0, c = 0, d = 0; ` `    ``for` `(``int` `i = 0; i < n; i++)  ` `    ``{ ` `        ``// Number of points on the left of Y-axis. ` `        ``if` `(p[i].x <= 0)          ` `            ``a++; ` ` `  `        ``// Number of points on the right of Y-axis. ` `        ``else` `if` `(p[i].x >= 0)  ` `            ``b++; ` ` `  `        ``// Number of points above X-axis. ` `        ``if` `(p[i].y >= 0)  ` `            ``c++; ` ` `  `        ``// Number of points below X-axis. ` `        ``else` `if` `(p[i].y <= 0)  ` `            ``d++; ` `    ``} ` ` `  `    ``return` `min({a, b, c, d}); ` `} ` ` `  `// Driver Function ` `int` `main() ` `{ ` `    ``Point p[] = { {1, 1}, {2, 2}, {-1, -1}, {-2, 2} }; ` `    ``int` `n = ``sizeof``(p)/``sizeof``(p[0]); ` `    ``cout << findmin(p, n); ` `    ``return` `0; ` `} `

 `// Java program to find minimum points to be moved  ` `// so that all points are on same side.  ` `import` `java.util.*; ` ` `  `class` `GFG ` `{ ` ` `  `// Structure to store the coordinates of a point.  ` `static` `class` `Point  ` `{  ` `    ``int` `x, y;  ` ` `  `    ``public` `Point(``int` `x, ``int` `y)  ` `    ``{ ` `        ``this``.x = x; ` `        ``this``.y = y; ` `    ``} ` `};  ` ` `  `// Function to find the minimum number of points  ` `static` `int` `findmin(Point p[], ``int` `n)  ` `{  ` `    ``int` `a = ``0``, b = ``0``, c = ``0``, d = ``0``;  ` `    ``for` `(``int` `i = ``0``; i < n; i++)  ` `    ``{  ` `        ``// Number of points on the left of Y-axis.  ` `        ``if` `(p[i].x <= ``0``)      ` `            ``a++;  ` ` `  `        ``// Number of points on the right of Y-axis.  ` `        ``else` `if` `(p[i].x >= ``0``)  ` `            ``b++;  ` ` `  `        ``// Number of points above X-axis.  ` `        ``if` `(p[i].y >= ``0``)  ` `            ``c++;  ` ` `  `        ``// Number of points below X-axis.  ` `        ``else` `if` `(p[i].y <= ``0``)  ` `            ``d++;  ` `    ``}  ` `    ``return` `Math.min(Math.min(a, b),  ` `                    ``Math.min(c, d));  ` `}  ` ` `  `// Driver Code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``Point p[] = {``new` `Point(``1``, ``1``), ``new` `Point(``2``, ``2``),  ` `                 ``new` `Point(-``1``, -``1``), ``new` `Point(-``2``, ``2``)}; ` `    ``int` `n = p.length; ` `    ``System.out.println(findmin(p, n)); ` `} ` `} ` ` `  `// This code is contributed by PrinciRaj1992 `

 `# Python3 program to find minimum points to be  ` `# moved so that all points are on same side. ` ` `  `# Function to find the minimum number ` `# of points ` `def` `findmin(p, n): ` ` `  `    ``a, b, c, d ``=` `0``, ``0``, ``0``, ``0` `    ``for` `i ``in` `range``(n):  ` `         `  `        ``# Number of points on the left  ` `        ``# of Y-axis. ` `        ``if` `(p[i][``0``] <``=` `0``):      ` `            ``a ``+``=` `1` ` `  `        ``# Number of points on the right  ` `        ``# of Y-axis. ` `        ``elif` `(p[i][``0``] >``=` `0``): ` `            ``b ``+``=` `1` ` `  `        ``# Number of points above X-axis. ` `        ``if` `(p[i][``1``] >``=` `0``): ` `            ``c ``+``=` `1` ` `  `        ``# Number of points below X-axis. ` `        ``elif` `(p[i][``1``] <``=` `0``): ` `            ``d ``+``=` `1` ` `  `    ``return` `min``([a, b, c, d]) ` ` `  `# Driver Code ` `p ``=` `[ [``1``, ``1``], [``2``, ``2``], [``-``1``, ``-``1``], [``-``2``, ``2``] ] ` `n ``=` `len``(p) ` `print``(findmin(p, n)) ` `     `  `# This code is contributed by Mohit Kumar `

 `// C# rogram to find minimum points to be moved  ` `// so that all points are on same side. ` `using` `System; ` `     `  `class` `GFG ` `{ ` ` `  `// Structure to store the coordinates of a point.  ` `public` `class` `Point  ` `{  ` `    ``public` `int` `x, y;  ` ` `  `    ``public` `Point(``int` `x, ``int` `y)  ` `    ``{ ` `        ``this``.x = x; ` `        ``this``.y = y; ` `    ``} ` `};  ` ` `  `// Function to find the minimum number of points  ` `static` `int` `findmin(Point []p, ``int` `n)  ` `{  ` `    ``int` `a = 0, b = 0, c = 0, d = 0;  ` `    ``for` `(``int` `i = 0; i < n; i++)  ` `    ``{  ` `        ``// Number of points on the left of Y-axis.  ` `        ``if` `(p[i].x <= 0)      ` `            ``a++;  ` ` `  `        ``// Number of points on the right of Y-axis.  ` `        ``else` `if` `(p[i].x >= 0)  ` `            ``b++;  ` ` `  `        ``// Number of points above X-axis.  ` `        ``if` `(p[i].y >= 0)  ` `            ``c++;  ` ` `  `        ``// Number of points below X-axis.  ` `        ``else` `if` `(p[i].y <= 0)  ` `            ``d++;  ` `    ``}  ` `    ``return` `Math.Min(Math.Min(a, b),  ` `                    ``Math.Min(c, d));  ` `}  ` ` `  `// Driver Code ` `public` `static` `void` `Main(String[] args) ` `{ ` `    ``Point []p = {``new` `Point(1, 1),  ` `                 ``new` `Point(2, 2),  ` `                 ``new` `Point(-1, -1), ` `                 ``new` `Point(-2, 2)}; ` `    ``int` `n = p.Length; ` `    ``Console.WriteLine(findmin(p, n)); ` `} ` `} ` `     `  `// This code is contributed by Princi Singh `

Output :
```1
```

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