g0801_0900.s0840_magic_squares_in_grid.Solution Maven / Gradle / Ivy
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Java-based LeetCode algorithm problem solutions, regularly updated
package g0801_0900.s0840_magic_squares_in_grid;
// #Medium #Array #Math #Matrix #2022_03_24_Time_0_ms_(100.00%)_Space_40.3_MB_(69.71%)
import java.util.HashSet;
import java.util.Set;
public class Solution {
public int numMagicSquaresInside(int[][] grid) {
int m = grid.length;
int n = grid[0].length;
int count = 0;
for (int i = 0; i < m - 2; i++) {
for (int j = 0; j < n - 2; j++) {
Set set = new HashSet<>();
int sum = grid[i][j] + grid[i][j + 1] + grid[i][j + 2];
if (sum == grid[i + 1][j] + grid[i + 1][j + 1] + grid[i + 1][j + 2]
&& sum == grid[i + 2][j] + grid[i + 2][j + 1] + grid[i + 2][j + 2]
&& sum == grid[i][j] + grid[i + 1][j] + grid[i + 2][j]
&& sum == grid[i][j + 1] + grid[i + 1][j + 1] + grid[i + 2][j + 1]
&& sum == grid[i][j + 2] + grid[i + 1][j + 2] + grid[i + 2][j + 2]
&& sum == grid[i][j] + grid[i + 1][j + 1] + grid[i + 2][j + 2]
&& sum == grid[i][j + 2] + grid[i + 1][j + 1] + grid[i + 2][j]
&& set.add(grid[i][j])
&& isLegit(grid[i][j])
&& set.add(grid[i][j + 1])
&& isLegit(grid[i][j + 1])
&& set.add(grid[i][j + 2])
&& isLegit(grid[i][j + 2])
&& set.add(grid[i + 1][j])
&& isLegit(grid[i + 1][j])
&& set.add(grid[i + 1][j + 1])
&& isLegit(grid[i + 1][j + 1])
&& set.add(grid[i + 1][j + 2])
&& isLegit(grid[i + 1][j + 2])
&& set.add(grid[i + 2][j])
&& isLegit(grid[i + 2][j])
&& set.add(grid[i + 2][j + 1])
&& isLegit(grid[i + 2][j + 1])
&& set.add(grid[i + 2][j + 2])
&& isLegit(grid[i + 2][j + 2])) {
count++;
}
}
}
return count;
}
private boolean isLegit(int num) {
return num <= 9 && num >= 1;
}
}