Suppose we have a string of parentheses; we have to write a function to compute the minimum number of parentheses to be removed to make the string correct (each open parenthesis is eventually closed).So, if the input is like "(()))(", then the output will be 2, as the correct string is "(())", remove ")(".To solve this, we will follow these steps −total := 0, temp := 0for each p in s, doif p is same as "(", thentotal := total + 1otherwise when p is same as ")" and total is not 0, thentotal := total - 1otherwise, temp := ... Read More

Suppose we have a list of numbers called nums and another number k, we can remove any sublist at most once from the list. We have to find the length of the longest resulting list such that the amount of numbers strictly less than k and strictly larger than k is the same.So, if the input is like nums = [6, 10, 8, 9, 3, 5], k = 6, then the output will be 5, as if we remove the sublist [9] then we will get [6, 10, 8, 3, 5] and there are two numbers [3, 5] which are ... Read More

Suppose we have a set of intervals; we have to find the minimum number of intervals that should be removed to make the rest of the intervals non-overlapping. So if the intervals are [[8, 10], [3, 5], [6, 9]], then the output will be 1, as we have to remove [6, 9] to make all others are non-overlapping.To solve this, we will follow these steps −n := size of arrayif n is 0, then return 0count := 1sort the array based on the end time of the intervalsend := end date of the first intervalfor i in range 1 to ... Read More

Suppose we have a linked list of numbers, we have to remove those numbers which appear multiple times in the linked list (hold only one occurrence in the output), we also have to maintain the order of the appearance in the original linked list.So, if the input is like [2 -> 4 -> 6 -> 1 -> 4 -> 6 -> 9], then the output will be [2 -> 4 -> 6 -> 1 -> 9].To solve this, we will follow these steps −if node is not null, thenl := a new settemp := nodeinsert value of temp into lwhile ... Read More

Suppose we have a list of numbers called nums and a list of operations. Here each operation has three fields [L, R, X], this indicated that we should increment by X all the elements from indices L to R (inclusive). We have to apply all operations and return the final list.So, if the input is like nums = [8, 4, 2, -9, 4] operations = [ [0, 0, 3], [1, 3, 2], [2, 3, 5] ], then the output will be [11, 6, 9, -2, 4], as the initial list was [8, 4, 2, -9, 4].Performing first operation [0, 0, ... Read More

Suppose we have an array of n non-negative integers. These are representing a height where the width of each bar is 1, we have to compute how much water it is able to catch after raining. So the map will be like −Here we can see there are 8 blue boxes, so the output will be 8.To solve this, we will follow these steps −Define a stack st, water := 0 and i := 0while i < size of heightif is stack is empty or height[stack top] >= height[i], then push i into stack, increase i by 1otherwisex := stack ... Read More

Suppose we have an array called nums, we have to find the product of elements of a contiguous subarray within an array (containing at least one number) which has the largest product. So if the array is [1, 9, 2, 0, 2, 5], the output will be 18, as contiguous subarray [1, 9, 2] has max product.To solve this, we will follow these steps −max_list := list of size nums, and fill with 0min_list := list of size nums, and fill with 0min_list := list of size nums, and fill with 0for i in range 1 to length of numsmax_list[i] ... Read More

Suppose we have postfix expression and we have to evaluate the value. Postfix expression is also known as Reverse polish notation. Here we have to use the stack data structure to solve the postfix expressions.So if the expression is “21+3*”, then the answer will be 9.Let us see the steps −for each character ch in the postfix expression, doif ch is an operator $\odot$ , thena := pop first element from stack, b := pop second element from the stackres := b $\odot$ apush res into the stackelse if ch is an operand, thenadd ch into the stackreturn element of ... Read More

Suppose we have two lists of same length they are called weights and values, and we also have another value capacity. Here weights[i] and values[i] represent the weight and value of the ith item. If we can take at most capacity weights, and that we can take any number of copies for each item, we have to find the maximum amount of value we can get.So, if the input is like weights = [1, 2, 3], values = [1, 5, 3], capacity = 5, then the output will be 11To solve this, we will follow these steps −Define a function ... Read More

Suppose we have a positive number n, we have to find the least number of perfect square numbers whose sum is same as n. So if the number is 10, then the output is 2, as the numbers are 10 = 9 + 1.To solve this, we will follow these steps −create one table for dynamic programming, of length n + 1, and fill it with infinitydp[0] := 0for i := 1, when i*i dp(n+1,INF);       dp[0] = 0;       for(int i =1;i*i