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0006-zigzag-conversion/0006-zigzag-conversion.java

@@ -0,0 +1,38 @@
+class Solution {
+    public String convert(String s, int numRows) {
+        //Define StringBuilders
+        StringBuilder[] sbs = new StringBuilder[numRows];
+        for(int i = 0; i < numRows; i++)
+        {
+            sbs[i] = new StringBuilder();
+        }
+
+        //Define Variables
+        char[] arr = s.toCharArray();
+        int n = arr.length;
+        int index = 0;
+
+        //Tranverse zig-zag
+        while(index < n)
+        {
+            //Go down
+            for(int j = 0; j < numRows && index < n; j++)
+            {
+                sbs[j].append(arr[index++]);
+            }
+            //Go up Before Start
+            for(int j = numRows - 2; j > 0 && index < n; j--)
+            {
+                sbs[j].append(arr[index++]);
+            }
+        }
+
+        //Combine all stringbuilders into one
+        StringBuilder res = sbs[0];
+        for(int i = 1; i < numRows; i++)
+        {
+            res.append(sbs[i].toString());
+        }
+        return res.toString();
+    }
+}

0006-zigzag-conversion/0006-zigzag-conversion.js

@@ -0,0 +1,20 @@
+function convert(s, numRows) {
+    if (numRows === 1 || numRows >= s.length) {
+        return s;
+    }
+
+    let rows = Array.from({ length: numRows }, () => '');
+    let idx = 0, step = 1;
+
+    for (let c of s) {
+        rows[idx] += c;
+        if (idx === 0) {
+            step = 1;
+        } else if (idx === numRows - 1) {
+            step = -1;
+        }
+        idx += step;
+    }
+
+    return rows.join('');
+}

0006-zigzag-conversion/0006-zigzag-conversion.php

@@ -0,0 +1,32 @@
+<?php
+
+class Solution {
+
+    /**
+     * @param String $s
+     * @param Integer $numRows
+     * @return String
+     */
+    function convert($s, $numRows) {
+    if ($numRows == 1 || $numRows >= strlen($s)) {
+        return $s;
+    }
+
+    $rows = array_fill(0, $numRows, '');
+    $idx = 0;
+    $step = 1;
+
+    for ($i = 0; $i < strlen($s); $i++) {
+        $rows[$idx] .= $s[$i];
+        if ($idx == 0) {
+            $step = 1;
+        } else if ($idx == $numRows - 1) {
+            $step = -1;
+        }
+        $idx += $step;
+    }
+
+    return implode('', $rows);
+}
+
+}

0006-zigzag-conversion/0006-zigzag-conversion.rb

@@ -0,0 +1,15 @@
+def convert(s, numRows)
+    return s if numRows == 1 || numRows >= s.length
+    rows = Array.new(numRows) { "" }
+    idx, step = 0, 1
+    s.each_char do |c|
+        rows[idx] += c
+        if idx == 0
+            step = 1
+        elsif idx == numRows - 1
+            step = -1
+        end
+        idx += step
+    end
+    rows.join("")
+end

3-longest-substring-without-repeating-characters/3-longest-substring-without-repeating-characters.cs

@@ -0,0 +1,16 @@
+public class Solution {
+    public int LengthOfLongestSubstring(string s) {
+        int n = s.Length;
+        HashSet<char> set = new HashSet<char>();
+        int maxLength = 0, i = 0, j = 0;
+        while (i < n && j < n) {
+            if (!set.Contains(s[j])) {
+                set.Add(s[j++]);
+                maxLength = Math.Max(maxLength, j - i);
+            } else {
+                set.Remove(s[i++]);
+            }
+        }
+        return maxLength;
+    }
+}

3-longest-substring-without-repeating-characters/3-longest-substring-without-repeating-characters.java

@@ -0,0 +1,16 @@
+class Solution {
+    public int lengthOfLongestSubstring(String s) {
+        int n = s.length();
+        Set<Character> set = new HashSet<>();
+        int maxLength = 0, i = 0, j = 0;
+        while (i < n && j < n) {
+            if (!set.contains(s.charAt(j))) {
+                set.add(s.charAt(j++));
+                maxLength = Math.max(maxLength, j - i);
+            } else {
+                set.remove(s.charAt(i++));
+            }
+        }
+        return maxLength;
+    }
+}

3-longest-substring-without-repeating-characters/3-longest-substring-without-repeating-characters.js

@@ -0,0 +1,14 @@
+var lengthOfLongestSubstring = function(s) {
+    let n = s.length;
+    let set = new Set();
+    let maxLength = 0, i = 0, j = 0;
+    while (i < n && j < n) {
+        if (!set.has(s.charAt(j))) {
+            set.add(s.charAt(j++));
+            maxLength = Math.max(maxLength, j - i);
+        } else {
+            set.delete(s.charAt(i++));
+        }
+    }
+    return maxLength;
+};

3-longest-substring-without-repeating-characters/3-longest-substring-without-repeating-characters.php

@@ -0,0 +1,26 @@
+<?php
+
+class Solution {
+
+    /**
+     * @param String $s
+     * @return Integer
+     */
+   function lengthOfLongestSubstring($s) {
+    $n = strlen($s);
+    $set = array();
+    $maxLength = 0;
+    $i = 0;
+    $j = 0;
+    while ($i < $n && $j < $n) {
+        if (!in_array($s[$j], $set)) {
+            $set[] = $s[$j++];
+            $maxLength = max($maxLength, $j - $i);
+        } else {
+            unset($set[array_search($s[$i++], $set)]);
+        }
+    }
+    return $maxLength;
+}
+
+}

3-longest-substring-without-repeating-characters/3-longest-substring-without-repeating-characters.rb

@@ -0,0 +1,16 @@
+def length_of_longest_substring(s)
+    n = s.length
+    set = Set.new
+    max_length, i, j = 0, 0, 0
+    while i < n && j < n
+        if !set.include?(s[j])
+            set.add(s[j])
+            j += 1
+            max_length = [max_length, j - i].max
+        else
+            set.delete(s[i])
+            i += 1
+        end
+    end
+    return max_length
+end

5-longest-palindromic-substring/5-longest-palindromic-substring.py

@@ -0,0 +1,28 @@
+class Solution:
+    def longestDupSubstring(self, S: str) -> str:
+        def rabin_karp(mid):
+            h = 0
+            for i in range(mid):
+                h = (h * 26 + nums[i]) % mod
+            s = {h}
+            p = pow(26, mid, mod)
+            for i in range(mid, len(S)):
+                h = (h * 26 + nums[i] - nums[i - mid] * p) % mod
+                if h in s:
+                    return i - mid + 1
+                s.add(h)
+            return -1
+
+        mod = 2**63 - 1
+        nums = [ord(c) - ord('a') for c in S]
+        left, right = 0, len(S)
+        index = -1
+        while left <= right:
+            mid = (left + right) // 2
+            pos = rabin_karp(mid)
+            if pos != -1:
+                left = mid + 1
+                index = pos
+            else:
+                right = mid - 1
+        return S[index:index + left - 1] if index != -1 else ""