Maximum Swap | 4 techniques | Leetcode 670

This video explains about the maximum swap problem using four techniques. The first technique is using bruteforce then using optimal 2 pass approach then using selection algorithm and finally using greedy algorithm which is the most optimal using only one pass.
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Largest number formed from an array: • Largest number formed ...
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[@BananaButcher]

The best part of this video is when he also says you can watch that video. which makes me easier to relate it with other problems. thanks for your work sir.

[@techdose4u]

Thanks! Glad you found it helpful.

[@anmolyadav9112]

best YT channel of DSA problem solving

[@techdose4u]

thanks for your appreciation :)

[@rishusingh.]

Best solution so far

[@techdose4u]

Thanks :)

[@sailendrachettri8521]

Thank You SirJi :)

[@techdose4u]

welcome :)

[@akriteesrivastava]

Thankyou so much your video are helping me a lot

[@techdose4u]

great 👍🏼

[@tindo0038]

you are the goat

[@techdose4u]

😅

[@RakeshChanda21]

time complexity is O(N^2) for first 2 approaches 2 parse and selection sort

[@techdose4u]

can you please elaborate ?

[@SaiDharahasReddyIndrakanti]

can we use montonic decreasing stack?

[@techdose4u]

you may have to try some tricks because if you see a lower value in future and pop then its wrong (L to R).
(R to L) decreasing stack again may not work as highest weight digits may have high value as compared to others. So, I wont use it

[@Lucifer-xt7un]

Will you please make a video about your dsa course so that it will give clarity whether to join or not as im very intrested but no proper guide is there about your course.

[@techdose4u]

I will make a private video and share on whatsapp. I hope you have queried us on whatsapp.

[@Lucifer-xt7un]

@@techdose4u yes sir

[@sajan_kharat]

I am not able to do any questions or projects. I understand everything when I watch the tutorial. I feel I am stuck in tutorial hell. Please help me

[@techdose4u]

UA-cam videos are only for you to solve one particular problem but cant help you with everything.
You can ping us on whatsapp to assist you.

[@mageshmcc]

The simplest answer is here, happy to explain if you need help :))
class Solution:
def maximumSwap(self, num: int) -> int:
num_list = [int(i) for i in str(num)]
max_iter = len(num_list) - 1
num_dict = {}
for i, x in enumerate(num_list):
if x not in num_dict:
num_dict[x] = [i]
else:
num_dict[x].append(i)
i = 0
while i < max_iter:
tmp_list = num_list[i::]
small = min(tmp_list)
big = max(tmp_list)
if num_list[i] == big:
pass
else:
ith_elm = num_list[i]
num_list[i] = big
num_list[num_dict[big][-1]] = ith_elm
break
i += 1
output_num = 0
digit_place = 10**max_iter
for i in num_list:
output_num += digit_place * i
digit_place //= 10
return output_num

[@techdose4u]

nice

[@RiteshKumar-IIT_KGP]

Your 2nd Method fails on test case for num=1993 🤡

[@techdose4u]

I think you can make the changes taking selection technique into consideration and playing with equality :)

[@RiteshKumar-IIT_KGP]

@@techdose4u if i would play with equality then another case num=98368 will fail 🤷

[@spetsnaz_2]

Mine got accepted. You might be doing something wrong. Code for your reference :
class Solution {
public:
int maximumSwap(int num) {
string s = to_string(num);
int n = s.size();
vector rightMax(n);
rightMax[n-1] = n-1;
for(int i=n-2; i>=0; i--) {
if(s[i] > s[rightMax[i+1]])
rightMax[i] = i;
else
rightMax[i] = rightMax[i+1];
}
for(int i=0; i

[@RiteshKumar-IIT_KGP]

@@techdose4u yeah u r right,ur 2nd method also worked.....
int maximumSwap(int num) {

vectorno;
int t=num;
while(t!=0){
no.push_back(t%10);
t=t/10;
}
reverse(no.begin(),no.end());
vectorind(no.size());
int n=no.size();
int maxi=INT_MIN;
int max_ind=n-1;
for(int i=n-1;i>=0;i--){
if(no[i]>maxi){
ind[i]=i;
max_ind=i;
maxi=no[i];
}
else if(no[i]