g0001_0100.s0073_set_matrix_zeroes.Solution Maven / Gradle / Ivy
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Java-based LeetCode algorithm problem solutions, regularly updated
package g0001_0100.s0073_set_matrix_zeroes;
// #Medium #Top_100_Liked_Questions #Top_Interview_Questions #Array #Hash_Table #Matrix
// #Udemy_2D_Arrays/Matrix #Big_O_Time_O(m*n)_Space_O(1)
// #2023_08_11_Time_1_ms_(79.07%)_Space_44.4_MB_(94.19%)
public class Solution {
// Approach: Use first row and first column for storing whether in future
// the entire row or column needs to be marked 0
public void setZeroes(int[][] matrix) {
int m = matrix.length;
int n = matrix[0].length;
boolean row0 = false;
boolean col0 = false;
// Check if 0th col needs to be market all 0s in future
for (int[] ints : matrix) {
if (ints[0] == 0) {
col0 = true;
break;
}
}
// Check if 0th row needs to be market all 0s in future
for (int i = 0; i < n; i++) {
if (matrix[0][i] == 0) {
row0 = true;
break;
}
}
// Store the signals in 0th row and column
for (int i = 1; i < m; i++) {
for (int j = 1; j < n; j++) {
if (matrix[i][j] == 0) {
matrix[i][0] = 0;
matrix[0][j] = 0;
}
}
}
// Mark 0 for all cells based on signal from 0th row and 0th column
for (int i = 1; i < m; i++) {
for (int j = 1; j < n; j++) {
if (matrix[i][0] == 0 || matrix[0][j] == 0) {
matrix[i][j] = 0;
}
}
}
// Set 0th column
for (int i = 0; i < m; i++) {
if (col0) {
matrix[i][0] = 0;
}
}
// Set 0th row
for (int i = 0; i < n; i++) {
if (row0) {
matrix[0][i] = 0;
}
}
}
}