784. Letter Case Permutation
阿新 • • 發佈:2018-02-21
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Given a string S, we can transform every letter individually to be lowercase or uppercase to create another string. Return a list of all possible strings we could create.
Examples: Input: S = "a1b2" Output: ["a1b2", "a1B2", "A1b2", "A1B2"] Input: S = "3z4" Output: ["3z4", "3Z4"] Input: S = "12345" Output: ["12345"]
把字符串裏的字母任意改為大寫或小寫,求能獲得的所有字符。
我的解決思路是一個個遍歷字符,碰到數字直接加上,碰的字母的,就把已經有的字符串復制一遍,前面一半字符串尾補加小寫字母,後面一半字符串尾補加大寫字母。
class Solution { public: vector<string> letterCasePermutation(string S) { vector<string> res(1); for (int i=0; i<S.length(); ++i) {char c = S[i]; int len = res.size(); if ((c>=‘a‘ && c <=‘z‘) || (c>=‘A‘ && c<=‘Z‘)) { for (int j=0; j<len; ++j) { res.push_back(res[j]); res[j].push_back(tolower(c)); res[j+len].push_back(toupper(c)); } } else for (int j=0; j<len; ++j) res[j].push_back(c); } return res; } };
784. Letter Case Permutation