Perfect Rectangle LeetCode Solution

Here, We see Perfect Rectangle LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

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Perfect Rectangle LeetCode Solution

Perfect Rectangle LeetCode Solution

Problem Statement

Given an array rectangles where rectangles[i] = [xi, yi, ai, bi] represents an axis-aligned rectangle. The bottom-left point of the rectangle is (xi, yi) and the top-right point of it is (ai, bi).

Return true if all the rectangles together form an exact cover of a rectangular region.

Example 1:

perectrec1 plane

Input: rectangles = [[1,1,3,3],[3,1,4,2],[3,2,4,4],[1,3,2,4],[2,3,3,4]]
Output: true
Explanation: All 5 rectangles together form an exact cover of a rectangular region.

Example 2:

perfectrec2 plane

Input: rectangles = [[1,1,2,3],[1,3,2,4],[3,1,4,2],[3,2,4,4]]
Output: false
Explanation: Because there is a gap between the two rectangular regions.

Example 3:

perfecrrec4 plane

Input: rectangles = [[1,1,3,3],[3,1,4,2],[1,3,2,4],[2,2,4,4]]
Output: false
Explanation: Because two of the rectangles overlap with each other.

Perfect Rectangle LeetCode Solution C++

class Solution {
 public:
  bool isRectangleCover(vector<vector<int>>& rectangles) {
    int n = rectangles.size();
    if (n == 1) return true;
    map<pair<int, int>, int> pointCounts;
    for (auto& rect : rectangles) {
      pointCounts[{rect[0], rect[1]}]++;
      pointCounts[{rect[2], rect[3]}]++;
      pointCounts[{rect[0], rect[3]}]--;
      pointCounts[{rect[2], rect[1]}]--;
    }
    int numMarks = 0;
    for (auto it = pointCounts.begin(); it != pointCounts.end(); it++) {
      if (it->second != 0) {
        if (abs(it->second) != 1) return false;
        numMarks++;
      }
    }
    return numMarks == 4;
  }
};Code language: PHP (php)

Perfect Rectangle LeetCode Solution Java

class Solution {
    public boolean isRectangleCover(int[][] rectangles) {
        if (rectangles.length == 0 || rectangles[0].length == 0) return false;
        Set<String> points = new HashSet<String>();
        int area = 0;
        int minX = Integer.MAX_VALUE;
        int minY = Integer.MAX_VALUE;
        int maxA = Integer.MIN_VALUE;
        int maxB = Integer.MIN_VALUE;
        for (int[] r : rectangles){
            int x = r[0];
            int y = r[1];
            int a = r[2];
            int b = r[3];
            area += (x-a) * (y-b);
            minX = Math.min(minX, x);
            minY = Math.min(minY, y);
            maxA = Math.max(maxA, a);
            maxB = Math.max(maxB, b);
            String bottomLeft = getHash(x,y);
            String topLeft = getHash(x,b);
            String bottomRight = getHash(a,y);
            String topRight = getHash(a,b);
            checkInSet(points, bottomLeft);
            checkInSet(points, topLeft);
            checkInSet(points, bottomRight);
            checkInSet(points, topRight);
        }
        String fullBottomLeft = getHash(minX,minY);
        String fullTopLeft = getHash(minX,maxB);
        String fullBottomRight = getHash(maxA,minY);
        String fullTopRight = getHash(maxA,maxB);
        if (points.size() != 4 || !points.contains(fullBottomLeft) 
            || !points.contains(fullTopLeft) || !points.contains(fullBottomRight) || !points.contains(fullTopRight)) return false;
        int fullArea = (minX-maxA) * (minY-maxB);
        return area == fullArea;
    }
    private void checkInSet(Set<String> points, String hash){
        if (!points.contains(hash)) points.add(hash);
        else points.remove(hash);
    }
    private String getHash(int x, int y){
        return x + ":" + y;
    }
}Code language: JavaScript (javascript)

Perfect Rectangle Solution JavaScript

var isRectangleCover = function(rectangles) {
   let corners = new Set();
   let l = Infinity, r = 0, t = 0, dummy = Infinity, area = 0;
   function key(x, y){
       return x + (y === 0 ? 0 : .1 / y);
   }
   function track(x, y){
       let n = key(x, y);
       if(corners.has(n)) corners.delete(n);
       else corners.add(n);
   }
   for(let i = 0; i < rectangles.length; i++){
       let[x1, y1, x2, y2] = rectangles[i];
       l = Math.min(l, x1);
       t = Math.max(t, y2);
       r = Math.max(r, x2);
       dummy = Math.min(dummy, y1);
       area += (x2 - x1) * (y2 - y1);
       track(x1, y1);
       track(x1, y2);
       track(x2, y1);
       track(x2, y2);
   }
   return (
       area === (t - dummy) * (r - l) 
       && 4 === corners.size
       && corners.has(key(l, dummy))
       && corners.has(key(r, dummy))
       && corners.has(key(l, t))
       && corners.has(key(r, t))
   )
};Code language: JavaScript (javascript)

Perfect Rectangle Solution Python

class Solution(object):
    def isRectangleCover(self, rectangles):
        area = 0
        corners = set()
        for x1, y1, x2, y2 in rectangles:
            area += (x2 - x1) * (y2 - y1)
            for corner in [(x1, y1), (x1, y2), (x2, y1), (x2, y2)]:
                if corner in corners:
                    corners.remove(corner)
                else:
                    corners.add(corner)
        if len(corners) != 4:
            return False
        x1, y1 = float("inf"), float("inf")
        x2, y2 = float("-inf"), float("-inf")
        for x, y in corners:
            x1 = min(x1, x)
            y1 = min(y1, y)
            x2 = max(x2, x)
            y2 = max(y2, y)
        union_area = (x2 - x1) * (y2 - y1)
        if area != union_area:
            return False
        return area == (x2 - x1) * (y2 - y1)    
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