[LeetCode] 520. Detect Capital

轉自LeetCode

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:

1. All letters in this word are capitals, like "USA".
2. All letters in this word are not capitals, like "leetcode".
3. Only the first letter in this word is capital if it has more than one letter, 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.

<Solution>

想法如下

• 計算大寫字母有幾個

• 當全是小寫或是全大寫，回傳 true

• 當只有一個大寫，且是第一個字母，回傳 true

• 其餘都回傳 false

code 如下
C++

	class Solution {
	public:
	bool detectCapitalUse(string word) {
	int cnt = 0;
	for(const auto &c : word) {
	if(isupper(c)) {
	++cnt;
	}
	}
	return ((cnt == 0 || cnt == word.length()) || (cnt == 1 && isupper(word[0])));
	}
	};

view raw detectCapital.cpp hosted with ❤ by GitHub

Java

	class Solution {
	public boolean detectCapitalUse(String word) {
	int cnt = 0;
	for(final char c : word.toCharArray()) {
	if(Character.isUpperCase(c)) {
	++cnt;
	}
	}
	return ((cnt == 0 || cnt == word.length()) || (cnt == 1 && Character.isUpperCase(word.charAt(0))));
	}
	}

view raw detectCapital.java hosted with ❤ by GitHub

Java 還可以使用 regular expression(參考)

	class Solution {
	public boolean detectCapitalUse(String word) {
	return word.matches("[A-Z]+|[a-z]+|[A-Z][a-z]+");
	}
	}

view raw detectCapital_2.java hosted with ❤ by GitHub