CODE EXAMPLE FOR CPP

Prefix Sum of Matrix (Or 2D Array)

# Python Program to find
# prefix sum of 2d array
R = 4
C = 5
 
# calculating new array
def prefixSum2D(a) :
    global C, R
    psa = [[0 for x in range(C)]
              for y in range(R)]
    psa[0][0] = a[0][0]
 
    # Filling first row
    # and first column
    for i in range(1, C) :
        psa[0][i] = (psa[0][i - 1] +
                       a[0][i])
    for i in range(0, R) :
        psa[i][0] = (psa[i - 1][0] +
                       a[i][0])
 
    # updating the values in
    # the cells as per the
    # general formula
    for i in range(1, R) :
        for j in range(1, C) :
 
            # values in the cells of
            # new array are updated
            psa[i][j] = (psa[i - 1][j] +
                         psa[i][j - 1] -
                         psa[i - 1][j - 1] +
                           a[i][j])
 
    # displaying the values
    # of the new array
    for i in range(0, R) :
        for j in range(0, C) :
            print (psa[i][j],
                   end = " ")
        print ()
 
# Driver Code
a = [[ 1, 1, 1, 1, 1 ],
     [ 1, 1, 1, 1, 1 ],
     [ 1, 1, 1, 1, 1 ],
     [ 1, 1, 1, 1, 1 ]]
 
prefixSum2D(a)
 
# This code is contributed by
# Manish Shaw(manishshaw1)