g1101_1200.s1139_largest_1_bordered_square.Solution Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-java Show documentation
Show all versions of leetcode-in-java Show documentation
Java-based LeetCode algorithm problem solutions, regularly updated
package g1101_1200.s1139_largest_1_bordered_square;
// #Medium #Array #Dynamic_Programming #Matrix #2022_03_05_Time_8_ms_(53.28%)_Space_48.1_MB_(29.34%)
public class Solution {
public int largest1BorderedSquare(int[][] grid) {
int[][] rightToLeft = new int[grid.length][];
int[][] bottomToUp = new int[grid.length][];
for (int i = 0; i < grid.length; i++) {
rightToLeft[i] = grid[i].clone();
bottomToUp[i] = grid[i].clone();
}
int row = grid.length;
int col = grid[0].length;
for (int i = 0; i < row; i++) {
for (int j = col - 2; j >= 0; j--) {
if (grid[i][j] == 1) {
rightToLeft[i][j] = rightToLeft[i][j + 1] + 1;
}
}
}
for (int j = 0; j < col; j++) {
for (int i = row - 2; i >= 0; i--) {
if (grid[i][j] == 1) {
bottomToUp[i][j] = bottomToUp[i + 1][j] + 1;
}
}
}
int res = 0;
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
int curLen = rightToLeft[i][j];
for (int k = curLen; k >= 1; k--) {
if (bottomToUp[i][j] >= k
&& rightToLeft[i + k - 1][j] >= k
&& bottomToUp[i][j + k - 1] >= k) {
if (k > res) {
res = k;
}
break;
}
}
}
}
return res * res;
}
}