Written in Java

Design a recursive algorithm to find the longest increasing sequence of numbers in a rectangular grid. For example, if the grid contains 97 47 56 36 35 57 41 13 89 36 98 75 25 45 26 17 then the longest increasing sequence of numbers is the sequence of length eight consisting of 17, 26, 36, 41, 47, 56, 57, 97. Note that there are no duplicates in the increasing sequence.

Java Code import java.util.Stack; public class LongestIncreasingSequence { private static void getLongestIncreasingSequence(int[][] grid, int r, int c) { int[][] g = new int[r][c]; for (int a = 0; a < r; a++) { for (int b = 0; b < c; b++) { g[a][b] = 1; } } int maxLen = -1; int idx1 = -1; int idx2 = -1; for(int a = 0; a < r; a++){ for(int b = 0; b < c; b++){ if(a > 0 && Math.abs(grid[a][b]-grid[a-1][b])==1){ g[a][b] = Math.max(g[a][b], g[a-1][b]+1); } if(b > 0 && Math.abs(grid[a][b]-grid[a][b-1])==1){ g[a][b] = Math.max(g[a][b], g[a][b-1]+1); } if(maxLen { maxLen = g[a][b]; idx1 = a; idx2 = b; } } } display(grid,g, maxLen, idx1, idx2); } private static void display(int[][] grid, int[][] g, int maxLen, int idx1, int idx2){ Stack s1 = new Stack<>(); while(maxLen >= 1){ s1.add(grid[idx1][idx2]); if(idx1>0 && Math.abs(g[idx1-1][idx2]-g[idx1][idx2])==1){ idx1--; } else if(idx2 >0 && Math.abs(g[idx1][idx2-1]-g[idx1][idx2])==1){ idx2--; } maxLen--; } Stack s2 = helper(s1); for(Integer integer : s2){ System.out.print(integer+" "); } } public static Stack helper(Stack input){ Stack tempStack = new Stack(); while(!input.isEmpty()){ int temp = input.pop(); while (!tempStack.isEmpty() && tempStack.peek() > temp){ input push(tempStack.pop()); } tempStack.push(temp); } return tempStack; } }