i wrote this code for min of distance of two strings s and t . but whatever i do it doesnt work for all tests i want

i want that the answer of these two test be 2

test 1 : s = "abbc" // t = "babb"

test2 : s = "aa" // t = "bb"

here is my code http://paste.ubuntu.com/11068656/ thank u so mcuh :)

PS : maybe it be obvious idk 'cause im a beginner :)