MadeEasy Full Length Test 2019: Programming & DS - DS

Question

Q.Consider a 2 dimensional array A[40 ... 95, 40 ... 95] in lower triangular matrix representation. If the array is implemented in the memory in the form of row major order and base address of the array is 1000, then the address of A[66][50] will be ________.

Comments

Lower triangular matrix will have elements in lower part of the principal diagonal of the matrix.

So, row 1 will have 1 element. row 2 will have 2 elements, like this...

Now starting from row 40 we have to go till 65. Number of rows=65-40+1=26.

Now till 26 rows number of elements will be 1+2+3......26. Which is 26*27/2=351.

Now, in row 66 we have to go till 10th column . so,add 10+351=361.

So, initial address is 1000+361=1361.

---

shouldn't we need to count till 50
40,41,42,43,44,45,46,47,48,49,50

this should be 11 because we have to give the address of [66,50]

correct me if i m wrong

---

But assume if we have to find address of A[41][41]. Will it be 1001 or 1002?. Our 1st element A[40[40] is starting from 1000. So, address of A[41][41] will be 1001. Right?.

---

oh our first element it at location 1000
now i got it thank you so much