The first time I wrote a programming interview question for Niu Ke: input a string and return the letter with the most occurrences of the string

Here is the little M who is preparing for the autumn move

Today I regained my confidence and challenged a simple algorithm problem (from Niu Ke, the link has been posted).You can think about it first
Counting the most letters in a string__Nioke.com(nowcoder.com)

After half an hour of coding, I found out why it is ok in vsCode, but it keeps getting an error no matter how I enter it!!!!Slowly fell into contemplation and began to get crazy !!!

Finally I fell asleep after constant thinking

The next day, I woke up struggling, turned on the computer, skillfully clicked on Niu Ke, and checked the analysis with one click

Unable to pass a single test case

With my unremitting efforts, I discovered the coding "secret" of online programming problems

Why my code in vscode is correct, but an error is reported when I enter the online editor

Premise: The code logic is correct

First of all, don't enter it in the form of a function, just write the logic code directly

Then how do I write test parameters

This is the most important secret I found:
readline();//Get the input string ``

In this way, the test data of the online editor can be directly obtained

like this

let str = readline();//Get the input string

If it is a fixed test data, you can only enter a fixed answer, so the test case cannot be passedlet str = 'aaccc' one of the reasons I'm getting an error is doing this

Secondly, remember to enter the answer

Solution ideas

Let's look at the topic again, that is, enter aab=> a , aaccc=>c , aabbcccdddddd=> d

We all know the truth. For me, the little white, the first thing that comes to mind is the subscript counting method

But obviously it won't work

Ideas:

1. Process the string, convert the string into an array to traverse each character (split() splits the string into an array)

2. Create a new map object to store each character key and the number of occurrences value (equivalent to a counter)

3. For loop traversal (for...in is also possible), and determine whether there is a current character in the key of the map, if it exists, value+1; if it does not exist, set one, and set the value to 0

4. Get the maximum value in the value of the map (through the loop, get the key while finding the maximum value)

 In this place, I made a mistake in my thinking at first. I want to use Math.max() to directly get the maximum value of values, and it is in one step, but it seems more troublesome for me to get the corresponding key.Math.max(...map.values())

5. Output

Code

let str = readline();//Get the input stringconst map=new Map()//Counterlet arr = str.split('') //split string into arrayfor(let i = 0 ; i < arr.length;i++){let val =map.get(arr[i])if(val){map.set(arr[i],val+1)}else{map.set(arr[i],1)}}let max=0; //Maximum valuelet keymap.forEach((v,k) => {if(max

In fact, the code is written like this, but pay attention to some features of the online editor

let str = 'aabbbcccccc'function countCase(str){//counterlet map=new Map()let str2 = str.split('')for(let i = 0 ; i < str2.length;i++){let val =map.get(str2[i])if(val){map.set(str[i],val+1)}else{map.set(str[i],1)}}let max=0;let keymap.forEach((v,k) => {if(max

When will Xiao Xiao Xiao Bai become an algorithm Xiao Bai?

If there is something wrong, welcome guidance

Reprint: Welcome to reprint, but this statement must be retained without the author's consent;