13. Roman to Integer Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, 2 is written as II in Roman numeral, just two one’s added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II. ...
1175. Prime Arrangements Return the number of permutations of 1 to n so that prime numbers are at prime indices (1-indexed.) (Recall that an integer is prime if and only if it is greater than 1, and cannot be written as a product of two positive integers both smaller than it.) Since the answer may be large, return the answer modulo 10^9 + 7. 1 2 3 4 5 6 7 8 9 10 Example 1: Input: n = 5 Output: 12 Explanation: For example [1,2,5,4,3] is a valid permutation, but [5,2,3,4,1] is not because the prime number 5 is at index 1. Example 2: Input: n = 100 Output: 682289015 Constraints: ...
1913. Maximum Product Difference Between Two Pairs The product difference between two pairs (a, b) and (c, d) is defined as (a * b) - (c * d). For example, the product difference between (5, 6) and (2, 7) is (5 * 6) - (2 * 7) = 16. Given an integer array nums, choose four distinct indices w, x, y, and z such that the product difference between pairs (nums[w], nums[x]) and (nums[y], nums[z]) is maximized. ...
50. Pow(x, n) Implement pow(x, n), which calculates x raised to the power n (i.e., xn). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Example 1: Input: x = 2.00000, n = 10 Output: 1024.00000 Example 2: Input: x = 2.10000, n = 3 Output: 9.26100 Example 3: Input: x = 2.00000, n = -2 Output: 0.25000 Explanation: 2-2 = 1/22 = 1/4 = 0.25 Constraints: ...
1071. Greatest Common Divisor of Strings For two strings s and t, we say “t divides s” if and only if s = t + … + t (t concatenated with itself 1 or more times) Given two strings str1 and str2, return the largest string x such that x divides both str1 and str2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Example 1: Input: str1 = "ABCABC", str2 = "ABC" Output: "ABC" Example 2: Input: str1 = "ABABAB", str2 = "ABAB" Output: "AB" Example 3: Input: str1 = "LEET", str2 = "CODE" Output: "" Example 4: Input: str1 = "ABCDEF", str2 = "ABC" Output: "" Constraints: ...
204. Count Primes Count the number of prime numbers less than a non-negative number, n. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Example 1: Input: n = 10 Output: 4 Explanation: There are 4 prime numbers less than 10, they are 2, 3, 5, 7. Example 2: Input: n = 0 Output: 0 Example 3: Input: n = 1 Output: 0 Constraints: ...
11004. Max Consecutive Ones III Given a binary array nums and an integer k, return the maximum number of consecutive 1’s in the array if you can flip at most k 0’s. 1 2 3 4 5 6 7 8 9 10 11 12 13 Example 1: Input: nums = [1,1,1,0,0,0,1,1,1,1,0], k = 2 Output: 6 Explanation: [1,1,1,0,0,1,1,1,1,1,1] Bolded numbers were flipped from 0 to 1. The longest subarray is underlined. Example 2: Input: nums = [0,0,1,1,0,0,1,1,1,0,1,1,0,0,0,1,1,1,1], k = 3 Output: 10 Explanation: [0,0,1,1,1,1,1,1,1,1,1,1,0,0,0,1,1,1,1] Bolded numbers were flipped from 0 to 1. The longest subarray is underlined. Constraints: ...
11. Container With Most Water Given n non-negative integers a1, a2, …, an , where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of the line i is at (i, ai) and (i, 0). Find two lines, which, together with the x-axis forms a container, such that the container contains the most water. Notice that you may not slant the container. ...
159. Longest Substring with At Most Two Distinct Characters Given a string s, return the length of the longest substring that contains at most two distinct characters. 1 2 3 4 5 6 7 8 9 10 11 Example 1: Input: s = "eceba" Output: 3 Explanation: The substring is "ece" which its length is 3. Example 2: Input: s = "ccaabbb" Output: 5 Explanation: The substring is "aabbb" which its length is 5. Constraints: ...
209. Minimum Size Subarray Sum Given an array of positive integers nums and a positive integer target, return the minimal length of a contiguous subarray [numsl, numsl+1, …, numsr-1, numsr] of which the sum is greater than or equal to target. If there is no such subarray, return 0 instead. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Example 1: Input: target = 7, nums = [2,3,1,2,4,3] Output: 2 Explanation: The subarray [4,3] has the minimal length under the problem constraint. Example 2: Input: target = 4, nums = [1,4,4] Output: 1 Example 3: Input: target = 11, nums = [1,1,1,1,1,1,1,1] Output: 0 Constraints: ...