MIsc Problems

package testrun;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.PriorityQueue;

class Program {

    public static class Node {
        int x;
        int y;
        int val;

        public int getX() {
            return x;
        }

        public void setX(int x) {
            this.x = x;
        }

        public int getY() {
            return y;
        }

        public void setY(int y) {
            this.y = y;
        }

        public int getVal() {
            return val;
        }

        public void setVal(int val) {
            this.val = val;
        }

        public Node(int x, int y, int val) {
            super();
            this.x = x;
            this.y = y;
            this.val = val;
        }

    }

    public static void KthLargestElem() {
        // matrix is sorted find kth largest,Soltion is klogn
        int mat[][] = { { 1, 5, 9 }, { 10, 11, 13 }, { 12, 13, 15 } };

        // create a max heap
        PriorityQueue<Node> minHeap = new PriorityQueue<Program.Node>(new Comparator<Node>() {
            @Override
            public int compare(Node o1, Node o2) {
                return o2.val - o1.val;
            }
        });
        // take required K
        int k = 7;
        // insert last column in max heap;
        for (int i = 0; i < mat.length; i++) {
            minHeap.offer(new Node(i, mat.length - 1, mat[i][mat.length - 1]));
        }

        // replace in max heap from previous column k times
        while (!minHeap.isEmpty()) {
            Node node = minHeap.poll();
            if (k == 1) {
                // output
                System.out.print(node.val);
            }

            if (node.y - 1 >= 0) {
                minHeap.offer(new Node(node.x, node.y - 1, mat[node.x][node.y - 1]));
            }
            k--;
        }

    }

    public static String longestPalindromicSubstring(String str) {
        if (str == null) {
            return null;
        }
        if (str.isEmpty() || str.length() == 1) {
            return str;
        }
        int maxLength = -1;
        String palinDrop = null;
        for (int i = 0; i < str.length(); i++) {
            // even length palindrom check
            int stattingIndex = -1;
            String currentPalindrop = null;
            int low = i - 1;
            int high = i;
            while (low >= 0 && high < str.length() && str.charAt(low) == str.charAt(high)) {
                if (high - low + 1 > maxLength) {
                    stattingIndex = low;
                    maxLength = high - low + 1;
                }
                low--;
                high++;
            }

            // odd length
            low = i - 1;
            high = i + 1;

            while (low >= 0 && high < str.length() && str.charAt(low) == str.charAt(high)) {
                if (high - low + 1 > maxLength) {
                    stattingIndex = low;
                    maxLength = high - low + 1;
                }
                low--;
                high++;
            }
            if (stattingIndex > -1 && maxLength > 0) {
                currentPalindrop = str.substring(stattingIndex, stattingIndex + maxLength);
                if (palinDrop == null || currentPalindrop != null && currentPalindrop.length() > palinDrop.length()) {
                    palinDrop = currentPalindrop;
                }
            }
        }

        return palinDrop;
    }

    static class MinMaxStack {
        ArrayList<HashMap<String, Integer>> minMaxMap = new ArrayList<HashMap<String, Integer>>();
        ArrayList<Integer>                  stack     = new ArrayList<Integer>();

        public Integer peek() {
            return (stack.get(stack.size() - 1));
        }

        public Integer pop() {
            minMaxMap.remove(minMaxMap.size() - 1);
            int returned = peek();
            stack.remove(stack.size() - 1);
            return returned;
        }

        public void push(Integer number) {

            HashMap<String, Integer> newTempMap = new HashMap<String, Integer>();
            newTempMap.put("min", number);
            newTempMap.put("max", number);
            int currentSieOfMap = minMaxMap.size();
            if (currentSieOfMap > 0) {
                HashMap<String, Integer> lastMinMax = minMaxMap.get(currentSieOfMap - 1);
                newTempMap.replace("min", Math.min(lastMinMax.get("min"), number));
                newTempMap.replace("max", Math.max(lastMinMax.get("max"), number));
            }
            minMaxMap.add(newTempMap);
            stack.add(number);
        }

        public Integer getMin() {
            return minMaxMap.get(minMaxMap.size() - 1).get("min");
        }

        public Integer getMax() {
            return minMaxMap.get(minMaxMap.size() - 1).get("max");
        }
    }

    public static ArrayList<ArrayList<Integer>> powerset(ArrayList<Integer> array) {
        ArrayList<ArrayList<Integer>> pSets = new ArrayList<ArrayList<Integer>>();
        // add empty set
        pSets.add(new ArrayList<Integer>());
        // for each number,get currenct poer set add that number in that set,add
        // new set in power set
        for (int curNum : array) {
            int lengthOfCurrentPowerSet = pSets.size();
            for (int index = 0; index < lengthOfCurrentPowerSet; index++) {
                ArrayList<Integer> curSet = new ArrayList<Integer>(pSets.get(index));
                curSet.add(curNum);
                pSets.add(curSet);
            }
        }
        return pSets;
    }

    public static ArrayList<ArrayList<Integer>> getPermutations(ArrayList<Integer> array) {
        ArrayList<ArrayList<Integer>> list = new ArrayList<ArrayList<Integer>>();
        generatePerm(array, new ArrayList<Integer>(), list);
        return list;
    }

    public static void generatePerm(ArrayList<Integer> array, ArrayList<Integer> currentPer,
            ArrayList<ArrayList<Integer>> finalListOfPermutation) {
        // when current processed array is process and current generated
        // permuation has elements it means we have covered all elements add it
        // in to final list
        if (array.isEmpty() && !currentPer.isEmpty()) {
            finalListOfPermutation.add(currentPer);
        }

        for (int i = 0; i < array.size(); i++) {
            // remove Ith elem from current array
            ArrayList<Integer> newarray = new ArrayList<Integer>(array);
            newarray.remove(i);
            // insert the ith elem in current permutation
            ArrayList<Integer> newperm = new ArrayList<Integer>(currentPer);
            newperm.add(array.get(i));
            // call recursion for this new array and current permutation
            generatePerm(newarray, newperm, finalListOfPermutation);
        }
    }

    public static ArrayList<Integer> riverSizes(int[][] matrix) {
        ArrayList<Integer> riverSizes = new ArrayList<Integer>();
        boolean[][] isVisited = new boolean[matrix.length][matrix[0].length];
        for (int i = 0; i < matrix.length; i++) {
            for (int j = 0; j < matrix[0].length; j++) {
                if (isVisited[i][j]) {
                    continue;
                }
                int currentRiverSize = 0;
                ArrayList<Integer[]> currentNodeList = new ArrayList<Integer[]>();
                currentNodeList.add(new Integer[] { i, j });
                while (currentNodeList.size() > 0) {
                    Integer[] curNode = currentNodeList.get(currentNodeList.size() - 1);
                    currentNodeList.remove(currentNodeList.size() - 1);
                    int x = curNode[0];
                    int y = curNode[1];
                    if (isVisited[x][y]) {
                        continue;
                    }
                    isVisited[x][y] = true;
                    if (matrix[x][y] == 0) {
                        continue;
                    }
                    currentRiverSize++;

                    // get four neighbours
                    if (x > 0 && !isVisited[x - 1][y]) {
                        currentNodeList.add(new Integer[] { x - 1, y });
                    }
                    if (x < matrix.length - 1 && !isVisited[x + 1][y]) {
                        currentNodeList.add(new Integer[] { x + 1, y });
                    }
                    if (y > 0 && !isVisited[x][y - 1]) {
                        currentNodeList.add(new Integer[] { x, y - 1 });
                    }
                    if (y < matrix[0].length - 1 && !isVisited[x][y + 1]) {
                        currentNodeList.add(new Integer[] { x, y + 1 });
                    }
                }
                if (currentRiverSize > 0) {
                    riverSizes.add(currentRiverSize);
                }

            }
        }
        return riverSizes;

    }

    public static ArrayList<Integer[]> threeNumberSum(int[] array, int targetSum) {
        ArrayList<Integer[]> list = new ArrayList<Integer[]>();
        if (array == null || array.length == 0) {
            return list;
        }
        // threeNumberSum(new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 15 }, 18);
        Arrays.sort(array);
        int n = array.length;
        int leftPointer = 0, rightPointer = 0, currentPointer = 0;
        for (int i = 0; i < n - 2; i++) {
            currentPointer = i;
            leftPointer = i + 1;
            rightPointer = n - 1;
            while (leftPointer < rightPointer) {
                if (targetSum == array[rightPointer] + array[currentPointer] + array[leftPointer]) {
                    Integer[] triplet = new Integer[] { array[currentPointer], array[leftPointer], array[rightPointer] };
                    Arrays.sort(triplet);
                    // for (int num : triplet) {
                    // System.out.print(" " + num);
                    // }
                    // System.out.println();
                    list.add(triplet);
                    rightPointer--;
                    leftPointer++;
                } else if (targetSum > array[rightPointer] + array[currentPointer] + array[leftPointer]) {
                    leftPointer++;
                } else if (targetSum < array[rightPointer] + array[currentPointer] + array[leftPointer]) {
                    rightPointer--;
                }
            }
        }
        return list;
    }

    public static int[] bubbleSort(int[] array) {
        if (array == null) {
            return null;
        } else if (array.length == 0) {
            return array;
        }
        int n = array.length;
        boolean swapped = false;
        for (int i = 0; i < n - 1; i++) {
            swapped = false;
            for (int j = 0; j < n - i - 1; j++) {
                if (array[j] > array[j + 1]) {
                    int temp = array[j];
                    array[j] = array[j + 1];
                    array[j + 1] = temp;
                    swapped = true;
                }
            }
            if (!swapped) {
                break;
            }
        }

        for (int i : array) {
            System.out.print("," + i);
        }
        return array;

    }

    public static int[] findThreeLargestNumbers(int[] array) {
        if (array == null || array.length == 0) {
            return null;
        }
        int[] largestThree = { Integer.MIN_VALUE, Integer.MIN_VALUE, Integer.MIN_VALUE };
        // maintain an array of size 3,which contains max elements traversed so
        // far
        for (int cur : array) {
            // whenever a new element comes and compare this from backward,it is
            // greater than replace it and shift current to previous position
            for (int k = 2; k >= 0; k--) {
                if (largestThree[k] < cur) {
                    int temp = largestThree[k];
                    largestThree[k] = cur;
                    for (int shift = k - 1; shift >= 0; shift--) {
                        int t = largestThree[shift];
                        largestThree[shift] = temp;
                        temp = t;
                    }
                    break;
                }
            }
        }
        for (int i : largestThree) {
            System.out.print("," + i);
        }
        return largestThree;
    }

    public static int findClosestValueInBst(testrun.BinaryTree.Node tree, int target) {
        if (tree == null) {
            return -1;
        }
        int value = tree.data;
        int rvlaue = 0, lvalue = 0;
        if (tree.data < target && tree.right != null) {
            rvlaue = findClosestValueInBst(tree.right, target);
        } else if (tree.data > target && tree.left != null) {
            lvalue = findClosestValueInBst(tree.left, target);
        }
        return Math.max(value, Math.max(rvlaue, lvalue));
    }

    static class BST {
        public int value;
        public BST left;
        public BST right;

        public BST(int value) {
            this.value = value;
        }
    }

    public static int[] twoNumberSum(int[] array, int targetSum) {
        // Write your code here.
        if (array == null || array.length == 0 || targetSum <= 0) {
            return null;
        }
        Arrays.sort(array);
        List<Integer> list = new ArrayList<Integer>();
        int k = array.length - 1;
        int i = 0;
        int count = 0;
        while (i < array.length && k >= 0 && k > i) {
            if (array[i] + array[k] == targetSum) {
                list.add(array[i]);
                list.add(array[k]);
                i++;
                k--;
            } else if (array[i] + array[k] > targetSum) {
                k--;
            } else {
                i++;
            }
        }
        int[] output = new int[list.size()];
        for (int num : list) {
            System.out.print(" " + num);
            output[count++] = num;
        }
        Arrays.sort(output);
        return output;

    }

    public static ArrayList<Integer[]> fourNumberSum(int[] array, int targetSum) {
        ArrayList<Integer[]> sumArray = new ArrayList<Integer[]>();
        HashSet<HashSet<Integer>> finalReturnSet = new HashSet<HashSet<Integer>>();
        HashMap<Integer, ArrayList<HashSet<Integer>>> mapForSum = new HashMap<Integer, ArrayList<HashSet<Integer>>>();
        if (array == null || array.length == 0) {
            return sumArray;
        }
        //maintain a sum map for two elements
        for (int i = 0; i < array.length; i++) {
            for (int j = i + 1; j < array.length; j++) {
                HashSet<Integer> set = new HashSet<Integer>();
                set.add(i);
                set.add(j);
                int sum = array[i] + array[j];
                if (mapForSum.containsKey(sum)) {
                    mapForSum.get(sum).add(set);
                } else {
                    ArrayList<HashSet<Integer>> l = new ArrayList<HashSet<Integer>>();
                    l.add(set);
                    mapForSum.put(sum, l);
                }
            }
        }
        //traverse the map fro cur sum and differnce from traget sum.
        for (int curSum : mapForSum.keySet()) {
            if (curSum < targetSum) {
                int diff = targetSum - curSum;
                if (mapForSum.containsKey(diff) && mapForSum.get(curSum) != null && mapForSum.get(diff) != null) {
                    for (HashSet<Integer> firstSet : mapForSum.get(curSum)) {
                        for (HashSet<Integer> secondSet : mapForSum.get(diff)) {
                            HashSet<Integer> finalset = new HashSet<Integer>();
                            finalset.addAll(firstSet);
                            finalset.addAll(secondSet);
                            if (finalset.size() == 4) {
                                finalReturnSet.add(finalset);
                            }
                        }
                    }
                }
                mapForSum.put(curSum, null);
            }
        }

        for (HashSet<Integer> set : finalReturnSet) {
            int count = 0;
            Integer[] cur = new Integer[4];
            for (int num : set) {
                cur[count++] = array[num];
            }
            sumArray.add(cur);
        }
        return sumArray;
    }

    public static int[] subarraySort(int[] array) {

        int[] retArr = new int[] { -1, -1 };
        int minOutOfOrder = Integer.MAX_VALUE;
        int maxOutOfOrder = Integer.MIN_VALUE;
        if (array != null && array.length > 0) {
            for (int i = 0; i < array.length; i++) {
                boolean isOutOfOrder = false;
                if (i == 0) {
                    if (array[i] > array[i + 1]) {
                        isOutOfOrder = true;
                    }
                } else if (i == array.length - 1) {
                    if (array[i] < array[i - 1]) {
                        isOutOfOrder = true;
                    }
                } else if (array[i] > array[i + 1] || array[i - 1] > array[i]) {
                    isOutOfOrder = true;
                }
                if (isOutOfOrder) {
                    minOutOfOrder = Math.min(minOutOfOrder, array[i]);
                    maxOutOfOrder = Math.max(maxOutOfOrder, array[i]);
                }
            }
            if (minOutOfOrder == Integer.MAX_VALUE) {
                return retArr;
            }
            int leftIndex = 0;
            while (array[leftIndex] <= minOutOfOrder) {
                leftIndex++;
            }
            int rightIndex = array.length - 1;
            while (array[rightIndex] >= maxOutOfOrder) {
                rightIndex--;
            }
            retArr[0] = leftIndex;
            retArr[1] = rightIndex;

        }

        return retArr;

    }

    public static int[] largestRange(int[] array) {
        int[] retArr = new int[] { -1, -1 };
        HashMap<Integer, Boolean> numMap = new HashMap<Integer, Boolean>();
        for (int i : array) {
            numMap.put(i, true);
        }
        int maxLength = 0;
        for (int num : array) {
            if (!numMap.containsKey(num)) {
                continue;
            }
            int curLength = -1;
            int left = num - 1;
            int right = num + 1;
            while (numMap.containsKey(left)) {
                left--;
                curLength++;
            }
            while (numMap.containsKey(right)) {
                right++;
                curLength++;
            }

            if (curLength > maxLength) {
                maxLength = curLength;
                retArr = new int[] { left + 1, right - 1 };
            }
        }
        return retArr;
    }

    public static int minRewards(int[] scores) {

        int reward = 0;

        int[] rewards = new int[scores.length];
        Arrays.fill(rewards, 1);

        for (int i = 1; i < scores.length; i++) {
            if (scores[i] > scores[i - 1]) {
                rewards[i] = rewards[i - 1] + 1;
            }
        }
        for (int i = scores.length - 2; i >= 0; i--) {
            if (scores[i] > scores[i + 1]) {
                rewards[i] = Math.max(rewards[i], rewards[i + 1] + 1);
            }
        }
        for (int num : rewards) {
            System.out.print(" " + num);
            reward += num;
        }
        return reward;

    }

    public static void main(String[] args) {
        // minRewards(new int[] { 8, 4, 2, 1, 3, 6, 7, 9, 5 });
        KthLargestElem();
        System.out.println();
    }
}