SumOfAllSubMatrices2.java

packageLecture9;

// time complexity: O(n^2)

publicclassSumOfAllSubMatrices2 {

publicstaticvoidmain(String[] args) {

int[][] arr = { { 1, 1 }, { 1, 1 } };

System.out.println(sum_of_submatrices(arr));
 }

publicstaticintsum_of_submatrices(int[][] arr) {
intsum = 0;
intlen = arr.length;

for (inti = 0; i < len; i++) {
for (intj = 0; j < len; j++) {

inttl = (i + 1) * (j + 1);
intbr = (len - i) * (len - j);

sum = sum + (tl * br) * arr[i][j];
 }
 }

returnsum;
 }
}