multiple pointer program added

Author: sanjaydeveloper15

Multiple-Pointers/is-subsequence.char.js

@@ -0,0 +1,39 @@
+
+// Write a function called isSubsequence which takes in two strings and checks whether the characters
+// in the first string form a subsequence of the characters in the second string. 
+// In other words, the function should check whether the characters in the first string appear somewhere 
+// in the second string, without their order changing.
+
+console.log('------------- solution 1 ---------------')
+const isSubsequence = (str1, str2) => {
+
+    var i = 0;
+    var j = 0;
+    if (!str1) return true;
+    while (j < str2.length) {
+        console.log(i, str1.length)
+        if (str2[j] === str1[i]) i++;
+        if (i === str1.length) return true;
+        j++;
+    }
+    return false;
+}
+
+console.log(isSubsequence('hello', 'hello world')); // true
+console.log(isSubsequence('sing', 'sting')); // true
+console.log(isSubsequence('abc', 'abracadabra')); // true
+console.log(isSubsequence('abc', 'acb')); // false (order matters)
+
+console.log('------------- solution 2 ---------------')
+const isSubsequence2 = (str1, str2) => {
+
+    if (str1.length === 0) return true
+    if (str2.length === 0) return false
+    if (str2[0] === str1[0]) return isSubsequence2(str1.slice(1), str2.slice(1))
+    return isSubsequence2(str1, str2.slice(1))
+}
+
+console.log(isSubsequence2('hello', 'hello world')); // true
+console.log(isSubsequence2('sing', 'sting')); // true
+console.log(isSubsequence2('abc', 'abracadabra')); // true
+console.log(isSubsequence2('abc', 'acb')); // false (order matters)