Eva's Dev Notes

var majorityElement = function (nums) {
  let newObj = {}
  for (let num of nums) {
    // console.log(num)
    (!newObj[num]) ? newObj[num] = 1 : newObj[num]++
  }
  // console.log(newObj)
  let nNum = nums.length / 2
  // console.log('nNum', nNum)
  for (let key in newObj) {
    if (newObj[key] > nNum) return key
  }

};

var majorityElement2 = function (nums) {
  let result;
  let count = 0;

  for (let elem of nums) {
    if (count === 0) {
      result = elem;
    }
    if (result === elem) {
      count++;
    } else {
      count--;
    }
  }

  return result;

};

var majorityElement = function (nums) {
  // 只要是 > n/3 就進入陣列
  let candidate1 = null;
  let candidate2 = null;
  let count1 = 0;
  let count2 = 0;

  for (let num of nums) {

    if (candidate1 === num) {
      count1++
    } else if (candidate2 === num) {
      count2++
    } else if (count1 === 0) {
      candidate1 = num;
      count1++
    } else if (count2 === 0) {
      candidate2 = num;
      count2++
    } else {
      count1--;
      count2--;
    }
  }

  console.log('data:', candidate1, candidate2)
  count1 = 0;
  count2 = 0;
  const res = [];

  limit = Math.floor(nums.length / 3)

  for (let num of nums) {
    if (candidate1 === num) count1++;
    else if (candidate2 === num) {
      count2++;
    }
  }
  if (count1 > limit) res.push(candidate1)
  if (count2 > limit) res.push(candidate2)
  console.log(res, count1, count2)
  return res

};
majorityElement([1, 2])

//會有 問題：Time Limit Exceeded
const rotateArray1 = function (nums, k) {
  //unshift 將給入的元素值放到最前面
  for (let i = 0; i < k; i++) {
    console.log('nums.pop()', nums.pop())
    nums.unshift(nums.pop());
  }
  console.log('num', nums)
  return nums;
}

const revNum = (nums, start, end) => {
  while (start < end) {

    [nums[start], nums[end]] = [nums[end], nums[start]]
    console.log('[nums[start], nums[end]]', [nums[start], nums[end]])
    start++;
    end--;
  }
  console.log(nums)
}
// revNum([1, 2, 3, 4], 0, 3)

const rotateArray2 = function (nums, k) {
  k = k % nums.length
  //先整個陣列 reverse
  nums.reverse()
  revNum(nums, 0, k - 1)
  revNum(nums, k, nums.length - 1)
}

test("username input should be rendered", () => {
  render(<Login />);
  const usernameInputEl = screen.getByPlaceholderText(/username/i);
  expect(usernameInputEl).toBeInTheDocument();
});

test("password input should be rendered", () => {
  render(<Login />);
  const passwordInputEl = screen.getByPlaceholderText(/password/i);
  expect(passwordInputEl).toBeInTheDocument();
});

test("button should be rendered", () => {
  render(<Login />);
  const buttonEl = screen.getByRole("button");
  expect(buttonEl).toBeInTheDocument();
});

test("username input should be empty", () => {
  render(<Login />);
  const usernameInputEl = screen.getByPlaceholderText(/username/i);
  expect(usernameInputEl.value).toBe("");
});

test("password input should be empty", () => {
  render(<Login />);
  const passwordInputEl = screen.getByPlaceholderText(/password/i);
  expect(passwordInputEl.value).toBe("");
});

test("button should be disabled", () => {
  render(<Login />);
  const buttonEl = screen.getByRole("button");
  expect(buttonEl).toBeDisabled();
});

test("error message should not be visible", () => {
  render(<Login />);
  const errorEl = screen.getByTestId("error");
  expect(errorEl).not.toBeVisible();
});

test("username input should change", () => {
  render(<Login />);
  const usernameInputEl = screen.getByPlaceholderText(/username/i);
  //模擬傳入的值
  const testValue = "test";

  fireEvent.change(usernameInputEl, { target: { value: testValue } });
  expect(usernameInputEl.value).toBe(testValue);
});

test("password input should change", () => {
  render(<Login />);
  const passwordInputEl = screen.getByPlaceholderText(/password/i);
  const testValue = "test";

  fireEvent.change(passwordInputEl, { target: { value: testValue } });
  expect(passwordInputEl.value).toBe(testValue);
});

test("button should not be disabled when inputs exist", () => {
  render(<Login />);
  const buttonEl = screen.getByRole("button");
  const usernameInputEl = screen.getByPlaceholderText(/username/i);
  const passwordInputEl = screen.getByPlaceholderText(/password/i);

  const testValue = "test";

  fireEvent.change(usernameInputEl, { target: { value: testValue } });
  fireEvent.change(passwordInputEl, { target: { value: testValue } });

  expect(buttonEl).not.toBeDisabled();
});

test('renders 3 list items', () => {
  render(<App />);
  const listItems = screen.getAllByRole("listitem");
  expect(listItems.length).toEqual(3);
});

test('renders title', () => {

	render(<App />);
	const title = screen.getByTestId("mytestid");
	expect(title).toBeInTheDocument();

});

test('sum should be 3', () => {
  render(<App />);
  const titleSum = screen.getByTitle("sum");
  expect(titleSum.textContent).toBe("3");
});

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} list1
 * @param {ListNode} list2
 * @return {ListNode}
 */

  var mergeTwoLists = function (l1, l2) {
    //current
    const dummy = new ListNode(-Infinity)
    //point dummy node
    let prev = dummy;
    while (l1 && l2) {
      if (l1.val <= l2.val) {
        prev.next = l1;
        //移動 prev list
        prev = l1
        //鏈錶指針 l1 就往後移動
        l1 = l1.next
      } else {
        prev.next = l2;
        prev = l2
        l2 = l2.next
      }
    }
    //如果 l1 是 null ,就是 l2
    if (!l1) prev.next = l2;
    if (!l2) prev.next = l1;
    return dummy.next
  };

  mergeTwoLists([1, 100], [3, 4, 6, 8])

var isValid = function (s) {
  const hashMap = { "(": ")", "{": "}", "[": "]" };
  const stack = [];
  for (let ch of s) {
    if (hashMap[ch]) {
      // ch is an opening bracket
      stack.push(hashMap[ch]);
    } else if (stack.length > 0 && stack[stack.length - 1] === ch) {
      //當空陣列裡面有值且陣列的最後一個值和 key 是一樣的就從陣列中刪除
      // ch is a closing bracket and top of stack matches
      stack.pop();
    } else {
      // ch is a closing bracket and top of the stack doesn't match
      return false;
    }
  }
  return stack.length === 0;
};

const path = require('path');

module.exports = {
  //預設路徑位置
  entry: './src/index.js',
  output: {
    //輸出位置名稱(filename),檔案位置
    path: path.resolve(__dirname, 'dist'),
    filename: 'bundle.js',
  },
};

//path.resolve(__dirname, 'dist')
// dirname當前資料夾路徑
//path.resolve 將相對路徑改為絕對路徑

const path = require('path');

module.exports = {
  //預設路徑位置
  entry: './src/index.js',
  output: {
    //輸出位置名稱(filename),檔案位置
    path: path.resolve(__dirname, 'dist'),
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.css$/i, //只要副檔名為 .css 就會使用以下
        use: ["style-loader", "css-loader"],
      },
    ],
  },
};

devServer: {
  static: {
    directory: path.join(__dirname, 'dist'),
		//contentBase: path.join(__dirname, 'dist'),
  },
  compress: true,
  port: 9000,
open: true //可以即時更新
},