leetcode/src/s0017_letter_combinations_of_a_phone_number.cpp

33 lines
1.1 KiB
C++
Raw Normal View History

2022-11-04 07:50:54 +00:00
#include "s0017_letter_combinations_of_a_phone_number.hpp"
vector<string> Solution::letterCombinations(string digits) {
unordered_map<string, vector<string>> map;
map["2"] = vector<string>{"a", "b", "c"};
map["3"] = vector<string>{"d", "e", "f"};
map["4"] = vector<string>{"g", "h", "i"};
map["5"] = vector<string>{"j", "k", "l"};
map["6"] = vector<string>{"m", "n", "o"};
map["7"] = vector<string>{"p", "q", "r", "s"};
map["8"] = vector<string>{"t", "u", "v"};
map["9"] = vector<string>{"w", "x", "y", "z"};
if (digits.length() == 0) {
return vector<string>{};
} else {
string last = digits.substr(digits.length() - 1, 1);
digits.pop_back();
vector<string> combinations = letterCombinations(digits);
if (combinations.size() == 0) {
combinations = {""};
}
vector<string> result = {};
for (int i{0}; i < map.at(last).size(); i++) {
vector<string> temp = combinations;
for (int j{0}; j < temp.size(); j++) {
temp[j] += map.at(last)[i];
}
result.insert(result.end(), temp.begin(), temp.end());
}
return result;
}
}