leetcode

Author: ayoubzulfiqar

DetectCapital/detect_capital.dart

@@ -0,0 +1,95 @@
+/*
+
+-* 520. Detect Capital *-
+
+
+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 "leet-code".
+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.
+
+
+*/
+
+extension Equals on String {
+  bool equals(Object anObject) {
+    if (identical(this, anObject)) {
+      return true;
+    }
+    if (anObject is String) {
+      String anotherString = anObject;
+      int n = codeUnits.length;
+      if (n == anotherString.codeUnits.length) {
+        List<int> v1 = codeUnits;
+        List<int> v2 = anotherString.codeUnits;
+        int i = 0;
+        while (n-- != 0) {
+          if (v1[i] != v2[i]) {
+            return false;
+          }
+          i++;
+        }
+        return true;
+      }
+    }
+    return false;
+  }
+}
+
+class A {
+  bool detectCapitalUse(String word) {
+    return word.toUpperCase().equals(word) ||
+        word.toLowerCase().equals(word) ||
+        word.codeUnitAt(0) == word.toUpperCase() &&
+            word
+                .substring(1, word.length)
+                .toLowerCase()
+                .equals(word.substring(1, word.length));
+  }
+}
+
+class B {
+  bool detectCapitalUse(String word) {
+    int count = 0;
+    for (String char in word.split(''))
+      if ('Z'.codeUnitAt(0) - char.codeUnitAt(0) >= 0) count++;
+    return ((count == 0 || count == word.length) ||
+        (count == 1 && 'Z'.codeUnitAt(0) - word.codeUnitAt(0) >= 0));
+  }
+}
+
+class C {
+  bool detectCapitalUse(String word) {
+    if (word == "") return false;
+    if (word.length == 1) return true;
+    if (word.codeUnitAt(0) >= 'a'.codeUnitAt(0) &&
+        word.codeUnitAt(1) < 'a'.codeUnitAt(0)) return false;
+    for (int i = 2; i < word.length; i++) {
+      if ((word.codeUnitAt(1) - 'a'.codeUnitAt(0) + 1) *
+              (word.codeUnitAt(i) - 'a'.codeUnitAt(0) + 1) <
+          0) {
+        return false;
+      }
+    }
+    return true;
+  }
+}

DetectCapital/detect_capital.go

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+package main
+
+import "strings"
+
+// 1. using strings' build-in func
+func detectCapitalUse(word string) bool {
+	return word == strings.ToLower(word) || word == strings.ToUpper(word) || word == strings.Title(strings.ToLower(word))
+}
+
+// 2. set condition for judging
+func isCapital(letter int32) bool {
+	return letter <= 'Z' && letter >= 'A'
+}
+
+/*
+func detectCapitalUse(word string) bool {
+	var condition = 0
+
+	for index, letter := range word {
+		switch isCapital(letter) {
+		case true:
+			if condition == 0 {
+				condition = 1
+				continue
+			} else if condition == 1 {
+				continue
+			} else if condition == 2 || condition == 3 {
+				return false
+			}
+		case false:
+			if condition == 0 {
+				condition = 2
+			} else if condition == 1{
+				if index == 1 {
+					condition = 3
+				} else {
+					return false
+				}
+			} else if condition == 2 || condition == 3{
+				continue
+			}
+		}
+	}
+
+	return true
+}
+
+*/

DetectCapital/detect_capital.md

@@ -0,0 +1,81 @@
+# 🔥 Detect Capital 🔥 || 3 Approaches || Simple Fast and Easy || with Explanation
+
+## Solution - 1
+
+### Extension to check the Equality between two Objects
+
+```dart
+extension Equals on String {
+  bool equals(Object anObject) {
+    if (identical(this, anObject)) {
+      return true;
+    }
+    if (anObject is String) {
+      String anotherString = anObject;
+      int n = codeUnits.length;
+      if (n == anotherString.codeUnits.length) {
+        List<int> v1 = codeUnits;
+        List<int> v2 = anotherString.codeUnits;
+        int i = 0;
+        while (n-- != 0) {
+          if (v1[i] != v2[i]) {
+            return false;
+          }
+          i++;
+        }
+        return true;
+      }
+    }
+    return false;
+  }
+}
+```
+
+```dart
+class Solution {
+  bool detectCapitalUse(String word) {
+    return word.toUpperCase().equals(word) ||
+        word.toLowerCase().equals(word) ||
+        word.codeUnitAt(0) != word.toUpperCase() &&
+            word
+                .substring(1, word.length)
+                .toLowerCase()
+                .equals(word.substring(1, word.length));
+  }
+}
+```
+
+## Solution - 2
+
+```dart
+class Solution {
+  bool detectCapitalUse(String word) {
+    int count = 0;
+    for (String char in word.split(''))
+      if ('Z'.codeUnitAt(0) - char.codeUnitAt(0) >= 0) count++;
+    return ((count == 0 || count == word.length) ||
+        (count == 1 && 'Z'.codeUnitAt(0) - word.codeUnitAt(0) >= 0));
+  }
+}
+```
+
+## Solution - 3
+
+```dart
+class Solution {
+  bool detectCapitalUse(String word) {
+    if (word == "") return false;
+    if (word.length == 1) return true;
+    if (word.codeUnitAt(0) >= 'a'.codeUnitAt(0) &&
+        word.codeUnitAt(1) < 'a'.codeUnitAt(0)) return false;
+    for (int i = 2; i < word.length; i++) {
+      if ((word.codeUnitAt(1) - 'a'.codeUnitAt(0) + 1) *
+              (word.codeUnitAt(i) - 'a'.codeUnitAt(0) + 1) <
+          0) {
+        return false;
+      }
+    }
+    return true;
+  }
+}
+```

README.md

@@ -174,6 +174,7 @@ This repo contain leetcode solution using DART and GO programming language. Most
 - [**841.** Keys and Rooms](KeysAndRooms/keys_and_rooms.dart)
 - [**886.** Possible Bipartition](PossibleBipartition/possible_bipartition.dart)
 - [**980.** Unique Paths III](UniquePathsIII/unique_paths_iii.dart)
+- [**520.** Detect Capital](DetectCapital/detect_capital.dart)
 
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