vector<string> letterCombinations(string digits) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
int letters[26] = {2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9};
results.clear();
vector<char> result;
doCombine(letters, result, digits, 0);
return results;
}
void doCombine(int letters[], vector<char> &result, string digits, int index) {
if (index == digits.size()) {
string str(result.begin(), result.end());
results.push_back(str);
}
for (int i = 0; i < 26; i++) {
if (letters[i] == digits[index] - '0') {
result.push_back('a' + i);
doCombine(letters, result, digits, index + 1);
result.pop_back();
}
}
}
void doCombine(char in[], char out[], int length, int recurLev, int start){
int i;
for(i=start; i<length; i++){
// Select current letter
out[recurLev] = in[i];
// Tack on NUL for printf
out[recurLev+1] = '\0';
printf("%s\n", out);
// Recurse if more letters in input
// if(i < length-1){
doCombine(in, out, length, recurLev+1, i+1);
// }
}
}
int combine(char in[]){
int length;
char* out;
length = strlen(in);
// Allocate output buffer
out = (char*)malloc(length + 1);
if(!out){
return 0; // Failed
}
// Enter recursive portion
doCombine(in, out, length, 0, 0);
free(out);
return 1; // Success
}
