g0501_0600.s0520_detect_capital.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0501_0600.s0520_detect_capital;

// #Easy #String #2022_07_25_Time_2_ms_(65.95%)_Space_42_MB_(74.10%)

/**
 * 520 - Detect Capital\.
 *
 * Easy
 *
 * 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"`.
 *
 * Given a string `word`, return `true` if the usage of capitals in it is right.
 *
 * **Example 1:**
 *
 * **Input:** word = "USA"
 *
 * **Output:** true
 *
 * **Example 2:**
 *
 * **Input:** word = "FlaG"
 *
 * **Output:** false
 *
 * **Constraints:**
 *
 * *   `1 <= word.length <= 100`
 * *   `word` consists of lowercase and uppercase English letters.
**/
public class Solution {
    public boolean detectCapitalUse(String word) {
        if (word == null || word.length() == 0) {
            return false;
        }
        int upper = 0;
        int lower = 0;
        int n = word.length();
        boolean firstUpper = Character.isUpperCase(word.charAt(0));
        for (int i = 0; i < n; i++) {
            if (Character.isUpperCase(word.charAt(i))) {
                upper++;
            } else if (Character.isLowerCase(word.charAt(i))) {
                lower++;
            }
        }
        if (firstUpper && upper > 1) {
            firstUpper = false;
        }
        return upper == n || lower == n || firstUpper;
    }
}