leetcode

Author: ayoubzulfiqar

IsomorphicStrings/isomorphic_strings.dart

@@ -0,0 +1,110 @@
+/*
+
+ -* Isomorphic Strings *-
+
+Given two strings s and t, determine if they are isomorphic.
+
+Two strings s and t are isomorphic if the characters in s can be replaced to get t.
+
+All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character, but a character may map to itself.
+
+
+
+Example 1:
+
+Input: s = "egg", t = "add"
+Output: true
+Example 2:
+
+Input: s = "foo", t = "bar"
+Output: false
+Example 3:
+
+Input: s = "paper", t = "title"
+Output: true
+
+
+Constraints:
+
+1 <= s.length <= 5 * 104
+t.length == s.length
+s and t consist of any valid ascii character.
+
+
+*/
+
+// class A {
+//   bool isIsomorphic(String s, String t) {
+//     Map<String, int>? table = {}, tTable = {};
+//     for (int i = 0; i < s.length; i++) {
+//       // 15 is magic number
+//       int bit = (1 << (i % 15));
+
+//       if( table[s[i]] != null){
+//         table[s[i]] |= bit;
+//       }
+
+//       tTable[t[i]] |= bit;
+
+//       if (table[s[i]] != tTable[t[i]]) {
+//         return false;
+//       }
+//     }
+
+//     return true;
+//   }
+// }
+
+class B {
+// Runtime: 625 ms, faster than 16.13% of Dart online submissions for Isomorphic Strings.
+// Memory Usage: 140.6 MB, less than 100.00% of Dart online submissions for Isomorphic Strings.
+  bool isIsomorphic(String s, String t) {
+    // Base case: for different length of two strings...
+    if (s.length != t.length) return false;
+    // Create two maps for s & t strings...
+    List<int> map1 = List.filled(256, 0);
+    List<int> map2 = List.filled(256, 0);
+    // Traverse all elements through the loop...
+    for (int idx = 0; idx < s.length; idx++) {
+      // Compare the maps, if not equal, return false...
+      if (map1[s.codeUnitAt(idx)] != map2[t.codeUnitAt(idx)]) return false;
+      // Insert each character if string s and t into seperate map...
+      map1[s.codeUnitAt(idx)] = idx + 1;
+      map2[t.codeUnitAt(idx)] = idx + 1;
+    }
+    return true; // Otherwise return true...
+  }
+}
+
+class C {
+// Runtime: 611 ms, faster than 16.13% of Dart online submissions for Isomorphic Strings.
+// Memory Usage: 144.2 MB, less than 64.52% of Dart online submissions for Isomorphic Strings.
+  bool isIsomorphic(String s, String t) {
+    Map mapS = {}, mapT = {};
+    for (int i = 0; i < s.length; i++) {
+      if (mapS[s[i]] != null && mapT[t[i]] != null) {
+        mapS[s[i]] = t[i];
+        mapT[t[i]] = s[i];
+      } else if (mapS[s[i]] != t[i] || mapT[t[i]] != s[i]) return false;
+    }
+    return true;
+  }
+}
+
+class D {
+  bool isIsomorphic(String s, String t) {
+    Map cypher = Map();
+    for (int i = 0; i < s.length; i++) {
+      if (cypher.containsKey(s[i])) {
+        //cypher.set(s[i], t[i]);
+        cypher.forEach((key, value) {
+          key = s[i];
+          value = t[i];
+        });
+      } else if (cypher.entries.contains(s.codeUnitAt(i)) != t.codeUnitAt(i)) {
+        return false;
+      }
+    }
+    return cypher.values.length == cypher.length;
+  }
+}

IsomorphicStrings/isomorphic_strings.go

@@ -0,0 +1,34 @@
+package main
+
+func isIsomorphic(s string, t string) bool {
+	if len(s) != len(t) {
+		return false
+	}
+
+	m := make(map[byte]byte)
+	mt := make(map[byte]byte)
+
+	for i := 0; i < len(s); i++ {
+		t1 := t[i]
+
+		if value, ok := m[t1]; ok {
+			if value != s[i] {
+				return false
+			}
+		} else {
+			m[t1] = s[i]
+		}
+
+		s1 := s[i]
+
+		if value, ok := mt[s1]; ok {
+			if value != t[i] {
+				return false
+			}
+		} else {
+			mt[s1] = t[i]
+		}
+	}
+
+	return true
+}

IsomorphicStrings/isomorphic_strings.md

@@ -0,0 +1,90 @@
+# 🔥 Isomorphic Strings 🔥 || 3 Solutions || Simple Fast and Easy || with Explanation
+
+## Solution - 1
+
+```dart
+class Solution {
+// Runtime: 625 ms, faster than 16.13% of Dart online submissions for Isomorphic Strings.
+// Memory Usage: 140.6 MB, less than 100.00% of Dart online submissions for Isomorphic Strings.
+  bool isIsomorphic(String s, String t) {
+    // Base case: for different length of two strings...
+    if (s.length != t.length) return false;
+    // Create two maps for s & t strings...
+    List<int> map1 = List.filled(256, 0);
+    List<int> map2 = List.filled(256, 0);
+    // Traverse all elements through the loop...
+    for (int idx = 0; idx < s.length; idx++) {
+      // Compare the maps, if not equal, return false...
+      if (map1[s.codeUnitAt(idx)] != map2[t.codeUnitAt(idx)]) return false;
+      // Insert each character if string s and t into separate map...
+      map1[s.codeUnitAt(idx)] = idx + 1;
+      map2[t.codeUnitAt(idx)] = idx + 1;
+    }
+    return true; // Otherwise return true...
+  }
+}
+```
+
+## Solution - 2
+
+```dart
+class C {
+// Runtime: 611 ms, faster than 16.13% of Dart online submissions for Isomorphic Strings.
+// Memory Usage: 144.2 MB, less than 64.52% of Dart online submissions for Isomorphic Strings.
+  bool isIsomorphic(String s, String t) {
+    // Second map to hold the value and key of second String (t)
+    // First map to hold the value and key of first String (s)
+    Map mapS = {}, mapT = {};
+    //iterating through each element of the string
+    for (int i = 0; i < s.length; i++) {
+        // if they both are not null means they have values
+      if (mapS[s[i]] != null && mapT[t[i]] != null) {
+        // so the first map will hold the each string element individually fo every element
+        // base on key and value
+        mapS[s[i]] = t[i];
+        mapT[t[i]] = s[i];
+        // this cause if their value is not same as the element of the each string
+      } else if (mapS[s[i]] != t[i] || mapT[t[i]] != s[i]) return false;
+    }
+    return true;
+  }
+}
+```
+
+## Solution - 3
+
+```go
+func isIsomorphic(s string, t string) bool {
+	if len(s) != len(t) {
+		return false
+	}
+
+	m := make(map[byte]byte)
+	mt := make(map[byte]byte)
+
+	for i := 0; i < len(s); i++ {
+		t1 := t[i]
+
+		if value, ok := m[t1]; ok {
+			if value != s[i] {
+				return false
+			}
+		} else {
+			m[t1] = s[i]
+		}
+
+		s1 := s[i]
+
+		if value, ok := mt[s1]; ok {
+			if value != t[i] {
+				return false
+			}
+		} else {
+			mt[s1] = t[i]
+		}
+	}
+
+	return true
+}
+
+```

README.md

@@ -71,6 +71,7 @@ This repo contain leetcode solution using DART and GO programming language. Most
 - [Number of Dice Rolls With Target Sum](NumberOfDiceRollsWithTargetSum/number_of_dice_rolls_with_target_sum.dart)
 - [Remove Linked List Elements](RemoveLinkedListElements/remove_linked_list_elements.dart)
 - [Minimum Time to Make Rope Colorful](MinimumTimeToMakeRopeColorful/minimum_time_to_make_rope_colorful.dart)
+- [Isomorphic Strings](IsomorphicStrings/isomorphic_strings.dart)
 
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