Amazon 面试代码挑战题目

src/test/java/com/ossez/codebank/interview/tests/AmazonTest.java

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+package com.ossez.codebank.interview.tests;
+
+import java.lang.reflect.Array;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Amazon
+ * 
+ * <pre>
+ * https://www.cwiki.us/display/ITCLASSIFICATION/Flatten+Nested+Arrays
+ * </pre>
+ * 
+ * @author YuCheng
+ *
+ */
+public class AmazonTest {
+
+	private final static Logger logger = LoggerFactory.getLogger(AmazonTest.class);
+
+	List<Integer> returnList = new ArrayList<Integer>();
+
+	/**
+	 * https://www.cwiki.us/display/ITCLASSIFICATION/Flatten+Nested+Arrays
+	 * 
+	 * FlattenNestedArrays
+	 */
+	@Test
+	public void testFlattenNestedArrays() {
+		logger.debug("Test FlattenNestedArrays");
+		int numRows = 3;
+		int numColumns = 3;
+		List<List<Integer>> area = new ArrayList<List<Integer>>();
+		List<Integer> a1 = new ArrayList<Integer>();
+		List<Integer> a2 = new ArrayList<Integer>();
+		List<Integer> a3 = new ArrayList<Integer>();
+
+		a1.add(1);
+		a1.add(0);
+		a1.add(0);
+
+		a2.add(1);
+		a2.add(0);
+		a2.add(0);
+
+		a3.add(1);
+		a3.add(9);
+		a3.add(1);
+		area.add(a1);
+		area.add(a2);
+		area.add(a3);
+
+		int countD = 0;
+
+		int x = 0;
+		int y = 0;
+
+		for (int i = 0; i < area.size(); i++) {
+			boolean found9 = false;
+			y = 0;
+
+			List<Integer> xList = area.get(i);
+			for (int j = 0; j < xList.size(); j++) {
+				if (xList.get(j) != 9) {
+					y++;
+				} else {
+					found9 = true;
+					break;
+				}
+
+			}
+
+			if (found9) {
+				break;
+			}
+
+			x++;
+
+		}
+
+		int carX = 0;
+		int carY = 0;
+
+		for (int k = 0; k < numRows * numRows; k++) {
+
+			String command = makeMove(carX, carY, numRows, numColumns, area);
+
+			if (command != null) {
+
+				if (command.equals("U")) {
+					carY = carY + 1;
+				}
+				if (command.equals("R")) {
+					carX = carX + 1;
+				}
+				if (command.equals("L")) {
+					carX = carX - 1;
+				}
+				if (command.equals("D")) {
+					carY = carY + 1;
+				}
+
+				countD = countD + 1;
+
+				if (carX == x && carY == y) {
+					break;
+				}
+			} else {
+				break;
+			}
+		}
+
+		System.out.println("---" + x + y);
+		System.out.println("--COUNT-" + countD );
+
+	}
+
+	/**
+	 * Java 8 Stream to Flatten array.
+	 * 
+	 * @param array
+	 * @return
+	 */
+	private static String makeMove(int carX, int carY, int numRows, int numColumns, List<List<Integer>> area) {
+		
+	
+
+		if ((carX + 1 <numRows) && area.get(carX + 1).get(carY) !=9 )
+			if (area.get(carX + 1).get(carY) == 1)
+				return "R";
+			else
+				return "F";
+		
+		
+		if ((carY + 1 <numColumns) && area.get(carX + 1).get(carY) !=9)
+			if (area.get(carX).get(carY + 1) == 1)
+				return "U";
+			else
+				return "F";
+
+		if (carX > 0 && area.get(carX + 1).get(carY) !=9 )
+			if (area.get(carX - 1).get(carY) == 1)
+				return "L";
+			else
+				return "F";
+
+		else if (carX > 0 && carY > 0 && area.get(carX - 1).get(carY - 1) == 1)
+			return "D";
+
+		return null;
+	}
+
+	/**
+	 * Loop And Recursive
+	 * 
+	 * @param inputArray
+	 * @return
+	 * @throws IllegalArgumentException
+	 */
+	private List<List<Integer>> nearestVegetarianRestaurant(int totalRestaurants, List<List<Integer>> allLocations, int numRestaurants) {
+		// WRITE YOUR CODE HERE
+
+		List<List<Integer>> ret = new ArrayList<List<Integer>>();
+		HashMap<Double, List<Integer>> mp = new HashMap<Double, List<Integer>>();
+		Double[] keyArray = new Double[totalRestaurants];
+
+		int i = 0;
+		for (List<Integer> al : allLocations) {
+			Double dis = getDis(al.get(0), al.get(1));
+			mp.put(dis, al);
+			keyArray[i] = dis;
+
+			i++;
+		}
+
+		Arrays.sort(keyArray);
+		for (int j = 0; j < numRestaurants; j++) {
+			ret.add(mp.get(keyArray[j]));
+		}
+
+		return null;
+	}
+
+	private Double getDis(int a, int b) {
+		// WRITE YOUR CODE HERE
+
+		return Math.sqrt(a * a + b * b);
+
+	}
+
+	/**
+	 * Java 8 Stream to Flatten array.
+	 * 
+	 * @param array
+	 * @return
+	 */
+	private static Stream<Object> java8Flatten(Object[] array) {
+		// int[] flatInt = java8Flatten(array).mapToInt(Integer.class::cast).toArray();
+		return Arrays.stream(array).flatMap(o -> o instanceof Object[] ? java8Flatten((Object[]) o) : Stream.of(o));
+
+	}
+
+}