A string is a list of characters containingonly letter ‘a’ to ‘z’. For example: “abcdefg”, “isun” are valid strings. “rocket323”is not a valid string. Asuffix of a string suf[i] is the list of characters at positions from i to n-1(positions are labeled from 0 to n – 1, n is length of the string). For thestring “hustacm”, suf[0] = “hustacm”, suf[1] = “ustacm”, suf[3] = “tacm”,suf[6] = “m”. Thesuffix list L of a string is a permutation of numbers from 0 to n-1(n is lengthof the string), which satisfy the following condition: suf[L[0]] < suf[L[1]] < suf[L[2]]< … < suf[L[n-1]]. Forthe string “aabac”, its suffix list is [0, 1, 3, 2, 4].
Herecomes the question: Given a string S and a suffix list L, you are to changeminimum number of characters of S so that the suffix list of the new string isequal to L.