refactor 436

fishercoder1534 · fishercoder1534 · commit 91bb8ce7161a · 2019-03-30T08:40:53.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_436.java b/src/main/java/com/fishercoder/solutions/_436.java
@@ -7,53 +7,75 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**436. Find Right Interval
+ *
+ * Given a set of intervals, for each of the interval i, check if there exists an interval j whose start
+ * point is bigger than or equal to the end point of the interval i, which can be called that j is on the "right" of i.
+ *
+ * For any interval i, you need to store the minimum interval j's index,
+ * which means that the interval j has the minimum start point to build the "right" relationship for interval i.
+ * If the interval j doesn't exist, store -1 for the interval i. Finally, you need output the stored value of each interval as an array.
+ *
+ * Note:
+ *
+ * You may assume the interval's end point is always bigger than its start point.
+ * You may assume none of these intervals have the same start point.
+ *
+ * Example 1:
+ * Input: [ [1,2] ]
+ * Output: [-1]
+ * Explanation: There is only one interval in the collection, so it outputs -1.
+ *
+ * Example 2:
+ * Input: [ [3,4], [2,3], [1,2] ]
+ * Output: [-1, 0, 1]
+ * Explanation: There is no satisfied "right" interval for [3,4].
+ * For [2,3], the interval [3,4] has minimum-"right" start point;
+ * For [1,2], the interval [2,3] has minimum-"right" start point.
+ *
+ * Example 3:
+ * Input: [ [1,4], [2,3], [3,4] ]
+ * Output: [-1, 2, -1]
+ * Explanation: There is no satisfied "right" interval for [1,4] and [3,4].
+ * For [2,3], the interval [3,4] has minimum-"right" start point.
+ * */
 
 public class _436 {
 
-    public static int[] findRightInterval(Interval[] intervals) {
-        if (intervals == null || intervals.length == 0) {
-            return new int[0];
-        }
-        int[] result = new int[intervals.length];
-        result[0] = -1;
-        Interval last = intervals[intervals.length - 1];
-        Interval first = intervals[0];
-        Map<Interval, Integer> map = new HashMap();
-        for (int i = 0; i < intervals.length; i++) {
-            map.put(intervals[i], i);
-        }
+    public static class Solution1 {
+        public int[] findRightInterval(Interval[] intervals) {
+            if (intervals == null || intervals.length == 0) {
+                return new int[0];
+            }
+            int[] result = new int[intervals.length];
+            result[0] = -1;
+            Interval last = intervals[intervals.length - 1];
+            Interval first = intervals[0];
+            Map<Interval, Integer> map = new HashMap();
+            for (int i = 0; i < intervals.length; i++) {
+                map.put(intervals[i], i);
+            }
 
-        Collections.sort(Arrays.asList(intervals), (o1, o2) -> o1.start - o2.start);
+            Collections.sort(Arrays.asList(intervals), (o1, o2) -> o1.start - o2.start);
 
-        for (int i = 1; i < intervals.length; i++) {
-            //TODO: use binary search for the minimum start interval for interval[i-1] instead of a while loop
-            int tmp = i - 1;
-            int tmpI = i;
-            while (tmpI < intervals.length && intervals[tmpI].start < intervals[tmp].end) {
-                tmpI++;
+            for (int i = 1; i < intervals.length; i++) {
+                //TODO: use binary search for the minimum start interval for interval[i-1] instead of a while loop
+                int tmp = i - 1;
+                int tmpI = i;
+                while (tmpI < intervals.length && intervals[tmpI].start < intervals[tmp].end) {
+                    tmpI++;
+                }
+                if (tmpI < intervals.length) {
+                    result[map.get(intervals[tmp])] = map.get(intervals[tmpI]);
+                } else {
+                    result[map.get(intervals[tmp])] = -1;
+                }
             }
-            if (tmpI < intervals.length) {
-                result[map.get(intervals[tmp])] = map.get(intervals[tmpI]);
-            } else {
-                result[map.get(intervals[tmp])] = -1;
+            if (result[intervals.length - 1] == 0 && last.end > first.start) {
+                result[intervals.length - 1] = -1;
             }
+            return result;
         }
-        if (result[intervals.length - 1] == 0 && last.end > first.start) {
-            result[intervals.length - 1] = -1;
-        }
-        return result;
     }
 
-
-    public static void main(String... args) {
-        Interval[] intervals = new Interval[3];
-//        intervals[0] = new Interval(1,4);
-//        intervals[1] = new Interval(2,3);
-//        intervals[2] = new Interval(3,4);
-
-        intervals[0] = new Interval(3, 4);
-        intervals[1] = new Interval(2, 3);
-        intervals[2] = new Interval(1, 2);
-        findRightInterval(intervals);
-    }
 }
diff --git a/src/test/java/com/fishercoder/_436Test.java b/src/test/java/com/fishercoder/_436Test.java
@@ -0,0 +1,33 @@
+package com.fishercoder;
+
+import com.fishercoder.common.classes.Interval;
+import com.fishercoder.solutions._436;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class _436Test {
+    private static _436.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _436.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        Interval[] intervals = new Interval[3];
+        intervals[0] = new Interval(3, 4);
+        intervals[1] = new Interval(2, 3);
+        intervals[2] = new Interval(1, 2);
+        solution1.findRightInterval(intervals);
+    }
+
+    @Test
+    public void test2() {
+        Interval[] intervals = new Interval[3];
+        intervals[0] = new Interval(1, 4);
+        intervals[1] = new Interval(2, 3);
+        intervals[2] = new Interval(3, 4);
+        solution1.findRightInterval(intervals);
+    }
+}
