246. Strobogrammatic Number - cocoder39/coco39_LC GitHub Wiki
while (start <= end)
to process input like "6"
; start < end
is not good here
bool isStrobogrammatic(string num) {
unordered_map<char, char> map{{'0', '0'}, {'1', '1'}, {'6', '9'}, {'8', '8'}, {'9', '6'}};
int start = 0, end = num.length() - 1;
while (start <= end) {
if (map.find(num[start]) == map.end() || map[num[start]] != num[end] || map.find(num[end]) == map.end() || map[num[end]] != num[start]) {
return false;
}
start++;
end--;
}
return true;
}