Formatted question description: https://leetcode.ca/all/520.html
520. Detect Capital (Easy)
Given a word, you need to judge whether the usage of capitals in it is right or not.
We define the usage of capitals in a word to be right when one of the following cases holds:
- All letters in this word are capitals, like "USA".
- All letters in this word are not capitals, like "leetcode".
- Only the first letter in this word is capital, like "Google".
Otherwise, we define that this word doesn’t use capitals in a right way.
Example 1:
Input: "USA" Output: True
Example 2:
Input: "FlaG" Output: False
Note: The input will be a non-empty word consisting of uppercase and lowercase latin letters.
Related Topics:
String
Solution 1.
// OJ: https://leetcode.com/problems/detect-capital/
// Time: O(N)
// Space: O(1)
class Solution {
public:
bool detectCapitalUse(string word) {
if (word.size() < 2) return true;
bool a = isupper(word[0]), b = isupper(word[1]), upper = a && b;
if (!a && b) return false;
for (int i = 2; i < word.size(); ++i) {
if (isupper(word[i]) > 0 != upper) return false;
}
return true;
}
};
Solution 2.
// OJ: https://leetcode.com/problems/detect-capital/
// Time: O(N)
// Space: O(1)
class Solution {
public:
bool detectCapitalUse(string word) {
int cnt = 0;
for (char c : word) cnt += isupper(c) > 0;
return !cnt || cnt == word.size() || cnt == 1 && isupper(word[0]);
}
};
Java
class Solution {
public boolean detectCapitalUse(String word) {
if (word == null)
return false;
int length = word.length();
if (length <= 1)
return true;
char c0 = word.charAt(0);
boolean firstCapital = isCapital(c0);
if (firstCapital) {
char prevC = word.charAt(1);
for (int i = 2; i < length; i++) {
char curC = word.charAt(i);
if (isCapital(prevC) ^ isCapital(curC))
return false;
prevC = curC;
}
return true;
} else {
for (int i = 1; i < length; i++) {
char c = word.charAt(i);
if (isCapital(c))
return false;
}
return true;
}
}
public boolean isCapital(char c) {
return c >= 'A' && c <= 'Z';
}
}