Arrangement Beautiful Arrangement II public int[] constructArray(int n, int k) { int[] list = new int[n]; // max(k) == n - 1 for (int i = 0, left = 1, right = n; left <= right; i++...

Theorem Triangle area using coordinates [T={\frac {1}{2}}{\big }(x_{A}-x_{C})(y_{B}-y_{A})-(x_{A}-x_{B})(y_{C}-y_{A}){\big }] Triangle inequality In a normed...

Euler’s Theorem In number theory, Euler’s theorem (also known as the Fermat–Euler theorem or Euler’s totient theorem) states that if \(n\) and \(a\) are coprime positive integers, then \(a\) raise...

Pour Water public int[] pourWater(int[] heights, int V, int K) { while (V > 0) { int i = K; while (i > 0 && heights[i] >= heights[i - 1]) { i--; ...

Greedy Minimum Swaps to Make Strings Equal public int minimumSwap(String s1, String s2) { int[] count = new int[2]; for (int i = 0; i < s1.length(); i++) { // ignores matched p...

A* Search A* search algorithm selects the path that minimizes f(n) = g(n) + h(n) where n is the next node on the path g(n) is the cost of the path from the start node to n h(n) is a heuri...

Index Map Longest Substring Without Repeating Characters Dynamic Programming Word Break public boolean wordBreak(String s, List<String> wordDict) { Set<String> dict = new HashSe...

Special Binary String public String makeLargestSpecial(String s) { List<String> list = new ArrayList<>(); int count = 0, i = 0, j = 0; // splits s into as many special stri...

Transformation String Transforms Into Another String public boolean canConvert(String str1, String str2) { if (str1.equals(str2)) { return true; } Map<Character, Character...

Zigzag Iterator public class ZigzagIterator { private Queue<Iterator<Integer>> q; public ZigzagIterator(List<Integer> v1, List<Integer> v2) { q = new Linke...