g0801_0900.s0835_image_overlap

Class Solution

java.lang.Object

g0801_0900.s0835_image_overlap.Solution

public class Solution
extends Object

835 - Image Overlap.

Medium

You are given two images, img1 and img2, represented as binary, square matrices of size n x n. A binary matrix has only 0s and 1s as values.

We translate one image however we choose by sliding all the 1 bits left, right, up, and/or down any number of units. We then place it on top of the other image. We can then calculate the overlap by counting the number of positions that have a 1 in both images.

Note also that a translation does not include any kind of rotation. Any 1 bits that are translated outside of the matrix borders are erased.

Return the largest possible overlap.

Example 1:

Input: img1 = [[1,1,0],[0,1,0],[0,1,0]], img2 = [[0,0,0],[0,1,1],[0,0,1]]

Output: 3

Explanation: We translate img1 to right by 1 unit and down by 1 unit. The number of positions that have a 1 in both images is 3 (shown in red).

Example 2:

Input: img1 = [[1]], img2 = [[1]]

Output: 1

Example 3:

Input: img1 = [[0]], img2 = [[0]]

Output: 0

Constraints:

• n == img1.length == img1[i].length
• n == img2.length == img2[i].length
• 1 <= n <= 30
• img1[i][j] is either 0 or 1.
• img2[i][j] is either 0 or 1.

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	largestOverlap(int[][] img1, int[][] img2)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

largestOverlap

public int largestOverlap(int[][] img1,
                          int[][] img2)