save changes

Author: Adrian333Dev

random/3sum.js

@@ -0,0 +1,30 @@
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+const threeSum = (nums) => {
+  nums.sort((a, b) => a - b);
+  const triplets = [];
+  for (let i = 0; i < nums.length - 2; i++) {
+    if (i > 0 && nums[i - 1] === nums[i]) continue;
+    let l = i + 1,
+      r = nums.length - 1;
+    while (l < r) {
+      const sum = nums[i] + nums[l] + nums[r];
+      if (sum === 0) {
+        triplets.push([nums[i], nums[l], nums[r]]);
+        while (l < r && nums[l] === nums[l + 1]) l++;
+        while (l < r && nums[r] === nums[r + 1]) r--;
+        l++, r--;
+      } else if (sum < 0) l++;
+      else r--;
+    }
+  }
+
+  return triplets;
+};
+
+// TEST
+console.log(threeSum([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])); // []
+console.log(threeSum([0, 0, 0, 0])); // [[0, 0, 0]]
+console.log(threeSum([-1, 0, 1, 2, -1, -4])); // [[0, 1, 2], [0, 3, 4]]

random/longest-consecutive-sequence.js

@@ -0,0 +1,26 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+const longestConsecutive = (nums) => {
+  const map = {};
+  let max = 0;
+  for (let num of nums) {
+    if (num in map) continue;
+    const left = map[num - 1] || 0;
+    const right = map[num + 1] || 0;
+    const sum = left + right + 1;
+    map[num] = sum;
+    map[num - left] = sum;
+    map[num + right] = sum;
+    max = Math.max(max, sum);
+  }
+  console.log(map);
+  return max;
+};
+
+// TEST
+console.log(longestConsecutive([100, 4, 200, 1, 3, 2])); // 4
+console.log(longestConsecutive([0, 3, 7, 2, 5, 8, 4, 6, 0, 1])); // 9
+console.log(longestConsecutive([1, 2, 0, 1])); // 3
+console.log(longestConsecutive([1, 2, 0, 1, 3, 4, 5, 6, 7, 8, 9, 10])); // 10

random/string-encode-and-decode.js

@@ -0,0 +1,56 @@
+class Solution {
+  #hStart = '[[';
+  #hEnd = ']]';
+  /**
+   * @param {string[]} strs
+   * @returns {string}
+   */
+  encode(strs) {
+    let encoded = '';
+    for (const str of strs) {
+      // encoded += this.#hStart + str.length + this.#hEnd;
+      encoded += this.#hStart;
+      for (let j = 0; j < str.length; j++) {
+        encoded += c.charCodeAt(0);
+        if (j < str.length - 1) encoded += ':';
+      }
+      encoded += this.#hEnd;
+    }
+    return encoded;
+  }
+
+  /**
+   * @param {string} str
+   * @returns {string[]}
+   */
+  decode(str) {
+    let decoded = [];
+    for (let i = 0; i < str.length; i++) {
+      let s = 0,
+        e = 0,
+        sFound = false,
+        eFound = false;
+      while (s < str.length) {
+        if (str.charAt(s) !== this.#hStart.charAt(0)) s++;
+        else if (str.slice(s, this.#hStart.length) === this.#hStart) {
+          sFound = true;
+          break;
+        } else s += this.#hStart.length;
+      }
+      e = s + 1;
+      while (e < str.length) {
+        if (str.charAt(e) !== this.#hEnd.charAt(0)) e++;
+        else if (str.slice(e, this.#hEnd.length) === this.#hEnd) {
+          eFound = true;
+          break;
+        } else e += this.#hEnd.length;
+      }
+      if (sFound && eFound) {
+        let decodedStr = '';
+        for (let i = s + this.#hStart.length; i < e; i++) {
+          let idxOfSeperator = 
+        }
+      }
+    }
+  }
+}

random/two-sum.js

@@ -0,0 +1,21 @@
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+const twoSum = (nums, target) => {
+  const map = {};
+  for (let i = 0; i < nums.length; i++) {
+    const num = nums[i], remain = target - num;
+    if (remain in map) return [map[remain], i];
+    else map[num] = i;
+  }
+  return [];
+};
+
+// TEST
+console.log(twoSum([2, 7, 11, 15], 9)); // [0, 1]
+console.log(twoSum([3, 2, 4], 6)); // [1, 2]
+console.log(twoSum([3, 3], 6)); // [0, 1]
+console.log(twoSum([3, 2, 3], 6)); // [0, 2]
+console.log(twoSum([4, 4, 3, 1, 2], 8)); // [0, 4]

random/valid-sudoku.js

@@ -0,0 +1,59 @@
+/**
+ * @param {character[][]} board
+ * @return {boolean}
+ */
+const isValidSudoku = (board) => {
+  const rows = Array(9)
+    .fill()
+    .map(() => Array(9).fill(0));
+  const cols = Array(9)
+    .fill()
+    .map(() => Array(9).fill(0));
+  const boxes = Array(9)
+    .fill()
+    .map(() => Array(9).fill(0));
+
+  for (let i = 0; i < 9; i++) {
+    for (let j = 0; j < 9; j++) {
+      const rowCell = board[i][j];
+      const colCell = board[j][i];
+      const boxCell = board[3 * Math.floor(i / 3) + Math.floor(j / 3)][3 * (i % 3) + (j % 3)];
+
+      if (rowCell !== '.') {
+        if (rows[i][rowCell - 1]) return false;
+        else rows[i][rowCell - 1]++;
+      }
+      if (colCell !== '.') {
+        if (cols[i][colCell - 1]) return false;
+        else cols[i][colCell - 1]++;
+      }
+      if (boxCell !== '.') {
+        if (boxes[i][boxCell - 1]) return false;
+        else boxes[i][boxCell - 1]++;
+      }
+    }
+  }
+
+  console.log('ROWS: ');
+  for (const row of rows) console.log(row.join(' '));
+  console.log('COLS: ');
+  for (const col of cols) console.log(col.join(' '));
+  console.log('BOXES: ');
+  for (const box of boxes) console.log(box.join(' '));
+
+  return true;
+};
+
+let board = [
+  ['5', '3', '.', '.', '7', '.', '.', '.', '.'],
+  ['6', '.', '.', '1', '9', '5', '.', '.', '.'],
+  ['.', '9', '8', '.', '.', '.', '.', '6', '.'],
+  ['8', '.', '.', '.', '6', '.', '.', '.', '3'],
+  ['4', '.', '.', '8', '.', '3', '.', '.', '1'],
+  ['7', '.', '.', '.', '2', '.', '.', '.', '6'],
+  ['.', '6', '.', '.', '.', '.', '2', '8', '.'],
+  ['.', '.', '.', '4', '1', '9', '.', '.', '5'],
+  ['.', '.', '.', '.', '8', '.', '.', '7', '9'],
+];
+
+console.log(isValidSudoku(board));