can place flowers done

Author: rampatra

src/main/java/com/leetcode/arrays/CanPlaceFlowers.java

@@ -0,0 +1,67 @@
+package com.leetcode.arrays;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Level: Easy
+ * Problem Link: https://leetcode.com/problems/can-place-flowers/
+ * Problem Description:
+ * Suppose you have a long flowerBed in which some of the plots are planted and some are not. However, flowers cannot
+ * be planted in adjacent plots - they would compete for water and both would die.
+ * <p>
+ * Given a flowerBed (represented as an array containing 0 and 1, where 0 means empty and 1 means not empty), and a
+ * number n, return if n new flowers can be planted in it without violating the no-adjacent-flowers rule.
+ * <p>
+ * Example 1:
+ * Input: flowerBed = [1,0,0,0,1], n = 1
+ * Output: True
+ * <p>
+ * Example 2:
+ * Input: flowerBed = [1,0,0,0,1], n = 2
+ * Output: False
+ * <p>
+ * Note:
+ * The input array won't violate no-adjacent-flowers rule.
+ * The input array size is in the range of [1, 20000].
+ * n is a non-negative integer which won't exceed the input array size.
+ *
+ * @author rampatra
+ * @since 2019-07-24
+ */
+public class CanPlaceFlowers {
+
+    /**
+     * Time Complexity: O(n)
+     * Space Complexity: O(1)
+     * Runtime: <a href="https://leetcode.com/submissions/detail/246312039/">1 ms</a>.
+     *
+     * @param flowerBed
+     * @param n
+     * @return
+     */
+    public static boolean canPlaceFlowers(int[] flowerBed, int n) {
+        int i = 0, count = 0;
+        while (i < flowerBed.length) {
+            if (flowerBed[i] == 0 && (i == 0 || flowerBed[i - 1] == 0) && (i == flowerBed.length - 1 || flowerBed[i + 1] == 0)) {
+                flowerBed[i++] = 1;
+                count++;
+            }
+            if (count >= n)
+                return true;
+            i++;
+        }
+        return false;
+    }
+
+    public static void main(String[] args) {
+        assertTrue(canPlaceFlowers(new int[]{0}, 0));
+        assertTrue(canPlaceFlowers(new int[]{0}, 1));
+        assertTrue(canPlaceFlowers(new int[]{1}, 0));
+        assertFalse(canPlaceFlowers(new int[]{1}, 1));
+        assertTrue(canPlaceFlowers(new int[]{1, 0, 0, 0, 1}, 1));
+        assertFalse(canPlaceFlowers(new int[]{1, 0, 0, 0, 1}, 2));
+        assertFalse(canPlaceFlowers(new int[]{1, 0, 0, 0, 0, 1}, 2));
+        assertTrue(canPlaceFlowers(new int[]{1, 0, 0, 0, 1, 0, 0}, 2));
+    }
+}