Even though we calculate the value of memo[r][c] only once, But still we call findMinPath(V,r,c) more than once. So it should have been taken care while calculating the time complexity.

For eg.

00

10 01

20 11 11 02

30 21 21 12 12 03

31 22 22 13

This should be the ideal call tree for a 3*3 matrix.
and hence the complexity should not be R*C.