为期五天刷题打卡 10-5 ~10-9

总感觉应该一周都打卡,不然很容易就忘了

不过还是继续吧

678 valid-parenthesis-string
implemented linkedList

implemented binary tree, insert, lookup, remove
1512

1486 XOROperation
1518 WaterBottles

977. Squares of a Sorted Array

1221. Split a String in Balanced Strings

note
int sort, array.sort((a,b)=>a-b)

今天随便补了个简单的面经
// 两两reverse：例子： n= 76859 返回：n = 67589。

const reverse = (num) => {
  newStr = [...num.toString()];
  for (let i = 0; i < newStr.length; i += 2) {
    temp = newStr[i];
    newStr[i] = newStr[i + 1];
    newStr[i + 1] = temp;
  }
  return newStr.join("");
};

200. Number of Islands

note
for(let rowIndex in grid){ gets all the index from 0...grid.length}
watch in detail if its a string or int
think through about edge cases

combinedtwoSortedArray
findDuplicate
arrayElementSum

native way to use destrcture ...arr1 then .sort , but not the most efficient
this can get you the key by filtering on value
Object.keys(dict).find((key) => dict[key] === 2);