**Look and Say - Amazon Top Interview Questions**

### Problem Statement :

The "look and say" sequence is defined as follows: beginning with the term 1, each subsequent term visually describes the digits appearing in the previous term. The first few terms are as follows: 1 11 <- 1 one 21 <- 2 ones 1211 <- 1 two, 1 one 111221 <- 1 one, 1 two, 2 ones 312211 <- 3 ones, 2 twos, 1 one Given an integer n, return the nth term of this sequence as a string. Constraints 1 ≤ n ≤ 40 Example 1 Input n = 3 Output "21" Example 2 Input n = 4 Output "1211" Example 3 Input n = 5 Output "111221"

### Solution :

` ````
Solution in C++ :
string solve(int n) {
string s = "1", t;
for (int i = 1; i < n; i++) {
for (int j = 0, k = 0; j < s.size();) {
char c = s[k];
k++;
while (k < s.size() && s[k] == s[k - 1]) k++;
t.append(to_string(k - j));
t.push_back(c);
j = k;
}
t.swap(s);
t.clear();
}
return s;
}
```

` ````
Solution in Python :
class Solution:
def solve(self, n):
s = "1"
for _ in range(n - 1):
temp = ""
for x, y in groupby(s):
temp += str(len(list(y))) + x
s = temp
return s
```

## View More Similar Problems

## QHEAP1

This question is designed to help you get a better understanding of basic heap operations. You will be given queries of types: " 1 v " - Add an element to the heap. " 2 v " - Delete the element from the heap. "3" - Print the minimum of all the elements in the heap. NOTE: It is guaranteed that the element to be deleted will be there in the heap. Also, at any instant, only distinct element

View Solution →## Jesse and Cookies

Jesse loves cookies. He wants the sweetness of all his cookies to be greater than value K. To do this, Jesse repeatedly mixes two cookies with the least sweetness. He creates a special combined cookie with: sweetness Least sweet cookie 2nd least sweet cookie). He repeats this procedure until all the cookies in his collection have a sweetness > = K. You are given Jesse's cookies. Print t

View Solution →## Find the Running Median

The median of a set of integers is the midpoint value of the data set for which an equal number of integers are less than and greater than the value. To find the median, you must first sort your set of integers in non-decreasing order, then: If your set contains an odd number of elements, the median is the middle element of the sorted sample. In the sorted set { 1, 2, 3 } , 2 is the median.

View Solution →## Minimum Average Waiting Time

Tieu owns a pizza restaurant and he manages it in his own way. While in a normal restaurant, a customer is served by following the first-come, first-served rule, Tieu simply minimizes the average waiting time of his customers. So he gets to decide who is served first, regardless of how sooner or later a person comes. Different kinds of pizzas take different amounts of time to cook. Also, once h

View Solution →## Merging Communities

People connect with each other in a social network. A connection between Person I and Person J is represented as . When two persons belonging to different communities connect, the net effect is the merger of both communities which I and J belongs to. At the beginning, there are N people representing N communities. Suppose person 1 and 2 connected and later 2 and 3 connected, then ,1 , 2 and 3 w

View Solution →## Components in a graph

There are 2 * N nodes in an undirected graph, and a number of edges connecting some nodes. In each edge, the first value will be between 1 and N, inclusive. The second node will be between N + 1 and , 2 * N inclusive. Given a list of edges, determine the size of the smallest and largest connected components that have or more nodes. A node can have any number of connections. The highest node valu

View Solution →