Added 17 solutions

2017-02-21 00:05:09 -06:00
parent d6dcb21ea4
commit ff6167d56c
25 changed files with 676 additions and 69 deletions
@@ -0,0 +1,42 @@
+//     Author: Rodney Shaghoulian
+//     Github: github.com/rshaghoulian
+// HackerRank: hackerrank.com/rshaghoulian
+
+import java.util.Scanner;
+import java.util.Stack;
+
+// All 3 queries (1:push, 2:delete, 3:print max) are all O(1) runtime
+public class Solution {
+    public static void main(String[] args) {
+        Stack<Integer> stack    = new Stack<Integer>();
+        Stack<Integer> maxStack = new Stack<Integer>(); // keeps track of maximums
+
+        Scanner scan = new Scanner(System.in);
+        int N = scan.nextInt();
+        
+        for (int i = 0; i < N; i++) {
+            int query = scan.nextInt();
+            switch (query) {
+                case 1:
+                    int x = scan.nextInt();
+                    stack.push(x);
+                    if (maxStack.isEmpty() || x >= maxStack.peek()) {
+                        maxStack.push(x);
+                    }
+                    break;
+                case 2:
+                    int poppedValue = stack.pop();
+                    if (poppedValue == maxStack.peek()) {
+                        maxStack.pop();
+                    }
+                    break;
+                case 3:
+                    System.out.println(maxStack.peek());
+                    break;
+                default:
+                    break;
+            }
+        }        
+        scan.close();
+    }
+}