解題、oop

javascript/LeetCode/Array/1464.js

@@ -59,6 +59,15 @@ var maxProduct = function (nums) {
 
     return (lastNumber - 1) * (secondLastNumber - 1);
 
+    // solution 2.
+    // 取得第一、第二大value，並將該陣列做切割…只取前兩個
+    // let sortNums = nums.sort((a,b) => b - a).slice(0,2);
+    // // 第一大元素
+    // let i = sortNums[0];
+    // // 第二大元素
+    // let j = sortNums[1];
+    // return (i - 1) * (j - 1);
+
 };
 const nums = [1, 5, 4, 5];
 // return 16 

javascript/LeetCode/Array/1572.js

@@ -1,52 +1,25 @@
-// 1572. Matrix Diagonal Sum
-// return the sum of the matrix diagonals. 返回正方形中對角線的總和
-// sum X =>
-// primary: 1 + 5 + 9 
-// secondary: 3 + 5 + 7
-
-// 1. 是二維陣列
-// 2. 判斷陣列length是奇數或偶數，共有幾個二維陣列
-// 3. 
-//  a.第一個二維陣列:找該array中位於第0個位置和最後一個位置的值，之後其他二維陣列則取往後移一個位置的值
-//  b.最後一個二維陣列:找該array中位於第0個位置和最後一個位置的值
-
-// 二維陣列
-// 判斷陣列length是奇數或偶數，共有幾個二維陣列
-// ==> 找第一個和最後一個二維陣列中，第0個位置和最後一個位置的值
-// 其他二維陣列則取往後移一個位置的值
-
-/*
-Input: mat = [[1,2,3],
-              [4,5,6],
-              [7,8,9]]
-Output: 25
-Explanation: Diagonals sum: 1 + 5 + 9 + 3 + 7 = 25
-Notice that element mat[1][1] = 5 is counted only once.
-*/
-
 /**
+ * 1572. Matrix Diagonal Sum
+ * 
  * @param {number[][]} mat
  * @return {number}
  */
-var diagonalSum = function (mat) {
-
+var diagonalSum = function(mat) {
+    // 二維陣列，裡面的陣列是奇數的，取該陣列偶數index值;裡面陣列是偶數的，取該陣列奇數index值
     let result = 0;
-    let j = mat[0].length - 1;
-    for (let i = 0; i < mat.length; i++, j--) {
-        if (i !== j) {
-            result += mat[i][j];
-        }
-        result += mat[i][i];
-
-        // $result += (i != j) ? mat[i][j] : mat[i][i];
-        // let end = endTime(start);
-        // console.log(end);
+    let len = mat.length;
+    let mid = Math.floor(len / 2 );
+    for (let i = 0; i < len; i++) {
+      result += mat[i][i];
+      result += mat[len - 1 - i][i];
+    }
+    if (len % 2 != 0) {
+      result -= mat[mid][mid];
     }
     return result;
 };
-const arr = [
-    [1, 2, 3],
-    [4, 5, 6],
-    [7, 8, 9]
-];
-console.log(diagonalSum(arr));
+let mat = [[1,2,3],[4,5,6],[7,8,9]];
+// Output: 25
+// Explanation: Diagonals sum: 1 + 5 + 9 + 3 + 7 = 25
+// Notice that element mat[1][1] = 5 is counted only once.
+console.log(diagonalSum(mat));

javascript/LeetCode/Array/1588.js

@@ -69,6 +69,17 @@ var sumOddLengthSubarrays = function (arr) {
         }
     }
     return count;
+
+    // solution 2.
+    // let ans = 0;
+    // for(let i = 0;i < arr.length;++i) {
+    //     let currentSum = 0;
+    //     for(let j = i;j < arr.length;++j) {
+    //         currentSum += arr[j];
+    //         ans += (j - i + 1) % 2 === 1 ? currentSum : 0;
+    //     }
+    // }
+    // return ans;
 };
 const arr = [1, 4, 2, 5, 3];
 console.log(sumOddLengthSubarrays(arr));

javascript/LeetCode/Array/1980.js

@@ -0,0 +1,16 @@
+/**
+ * 1980. Find Unique Binary String
+ * 
+ * @param {string[]} nums
+ * @return {string}
+ */
+var findDifferentBinaryString = function(nums) {
+  let res = "";
+  for(let i = 0;i < nums.length;i++) {
+    res += (nums[i][i] === '0' ? '1' : '0');
+  }
+  return res;
+};
+let nums = ["01","10"];
+// "11"
+// console.log(findDifferentBinaryString(nums));

javascript/LeetCode/math/165.js

@@ -0,0 +1,34 @@
+/**
+ * 165. Compare Version Numbers
+ * 
+ * 參數為兩個字串，其內含有"."，將參數依據"."拆成左右兩部份，從左到右比較每個部份大小。
+ * 
+ * If version1 < version2, return -1.
+ * If version1 > version2, return 1.
+ * Otherwise, return 0.
+ * 
+ * 若部份的前面有0，則忽略0，取整數
+ * 
+ * @param {string} version1
+ * @param {string} version2
+ * @return {number}
+ */
+var compareVersion = function(version1, version2) {
+  let splitV1 = version1.split("."),splitV2 = version2.split(".");
+  let length = Math.max(splitV1.length, splitV2.length);
+  for(let i = 0;i < length;i++) {
+    let num1 = parseInt(splitV1[i]) || 0;
+    let num2 = parseInt(splitV2[i]) || 0;
+
+    if(num1 === num2){
+      continue;
+    }
+    return num1 > num2 ? 1 : -1;
+  }
+  return 0;
+};
+// let version1 = "1.2", version2 = "1.10"
+// -1
+let version1 = "1.01", version2 = "1.001";
+// 0
+console.log(compareVersion(version1,version2))

javascript/LeetCode/math/3099.js

@@ -0,0 +1,32 @@
+/**
+ * 3099. Harshad Number
+ * 
+ * Harshad:能被其各位數字之和整除
+ * 如果 x 是Harshad，則傳回 x 各位數字總和；否則，回傳 -1。
+ * @param {number} x
+ * @return {number}
+ */
+var sumOfTheDigitsOfHarshadNumber = function(x) {
+    // let split = x.toString().split("");
+    // let sum = 0;
+    // for(let i = 0;i < split.length;i++) {
+    //   sum+=parseInt(split[i]);
+    // }
+    // if(x % sum === 0){
+    //   return sum;
+    // }
+    // return -1;
+
+    // solution 2.
+    let ans = 0;
+    let temp = x;
+    while(temp > 0){
+      // 取尾數
+      ans += temp % 10;
+      temp = Math.floor(temp / 10);
+    }
+    return x % ans === 0 ? ans : -1;
+};
+let x = 18;
+// 9
+console.log(sumOfTheDigitsOfHarshadNumber(x));

javascript/LeetCode/math/3602.js

@@ -0,0 +1,21 @@
+/**
+ * 3602. Hexadecimal and Hexatrigesimal Conversion
+ * 
+ * hexadecimal = base 16，使用數字0 - 9和大寫A - F代表0 - 15
+ * hexatrigesimal = base 16，使用數字0 - 9和大寫A - Z代表0 - 35
+ * 取得hexadecimal的n的二次方(n * 2)和hexatrigesimal的n的三次方（n * 3)串連
+ * @param {number} n
+ * @return {string}
+ */
+var concatHex36 = function(n) {
+  return ((n ** 2).toString(16) + (n ** 3).toString(36)).toUpperCase();
+};
+let n = 36
+/** 
+ * Output: "5101000"
+n2 = 36 * 36 = 1296. In hexadecimal, it converts to (5 * 162) + (1 * 16) + 0 = 1296, which corresponds to "510".
+n3 = 36 * 36 * 36 = 46656. In hexatrigesimal, it converts to (1 * 363) + (0 * 362) + (0 * 36) + 0 = 46656, which corresponds to "1000".
+Concatenating both results gives "510" + "1000" = "5101000".
+ * 
+*/
+console.log(concatHex36(n));

javascript/index.js

@@ -1,4 +1,5 @@
 // debugger
+import { format } from 'node:path';
 import {ExecutionTimer} from './time.js';
 import assert from 'node:assert/strict';
 
@@ -1028,3 +1029,20 @@ var closetPair = function(arr1,arr2,x) {
 // [1,30];
 // console.log(closetPair(arr1,arr2,x));
 
+/**
+ * 166. Fraction to Recurring Decimal
+ * 
+ * 參數為分子、分母，以字串資料型態回傳分數 
+ * 如果小數部分重複，則將重複部分放在括號中。
+ * 若有很多個答案，任一回傳
+ * 
+ * @param {number} numerator
+ * @param {number} denominator
+ * @return {string}
+ */
+var fractionToDecimal = function(numerator, denominator) {
+
+};
+let numerator = 1, denominator = 2;
+// "0.5"
+// console.log(fractionToDecimal(numerator,denominator));

javascript/oop.js

@@ -0,0 +1,5 @@
+// 具名匯出 (Named Export)，使用{}，匯出多個獨立的功能
+import { Vehicle } from "./oop/Vehicle.js ";
+
+car = new Vehicle("Ford","Kuga");
+console.log(car.startEngine())