refactor 435

fishercoder1534 · fishercoder1534 · commit 9ca9c856222d · 2021-10-13T10:44:49.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_435.java b/src/main/java/com/fishercoder/solutions/_435.java
@@ -10,25 +10,20 @@ public static class Solution1 {
          * credit:: https://discuss.leetcode.com/topic/65828/java-solution-with-clear-explain
          * and https://discuss.leetcode.com/topic/65594/java-least-is-most
          * Sort the intervals by their end time, if equal, then sort by their start time.
+         * Then merge based on ending time.
          */
         public int eraseOverlapIntervals(int[][] intervals) {
-            Collections.sort(Arrays.asList(intervals), (o1, o2) -> {
-                if (o1[1] != o2[1]) {
-                    return o1[1] - o2[1];
+            Arrays.sort(intervals, (a, b) -> a[1] != b[1] ? a[1] - b[1] : a[0] - b[0]);
+            int erasures = 0;
+            int end = intervals[0][1];
+            for (int i = 1; i < intervals.length; i++) {
+                if (intervals[i][0] < end) {
+                    erasures++;
                 } else {
-                    return o2[0] - o1[0];
-                }
-            });
-            int end = Integer.MIN_VALUE;
-            int count = 0;
-            for (int[] interval : intervals) {
-                if (interval[0] >= end) {
-                    end = interval[1];
-                } else {
-                    count++;
+                    end = intervals[i][1];
                 }
             }
-            return count;
+            return erasures;
         }
     }
 
diff --git a/src/test/java/com/fishercoder/_435Test.java b/src/test/java/com/fishercoder/_435Test.java
@@ -1,5 +1,6 @@
 package com.fishercoder;
 
+import com.fishercoder.common.utils.CommonUtils;
 import com.fishercoder.solutions._435;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -16,8 +17,8 @@ public static void setup() {
 
     @Test
     public void test1() {
-        int[][] intervals = new int[][]{new int[]{1, 100}, new int[]{11, 22}, new int[]{1, 11}, new int[]{2, 12}};
-        assertEquals(2, solution1.eraseOverlapIntervals(intervals));
+        int[][] intervals = CommonUtils.convertLeetCodeIrregularLengths2DArrayInputIntoJavaArray("[1,2],[2,3],[3,4],[1,3]");
+        assertEquals(1, solution1.eraseOverlapIntervals(intervals));
     }
 
 }

Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,6 @@`
`1`	`1`	`package com.fishercoder;`
`2`	`2`
	`3`	`+import com.fishercoder.common.utils.CommonUtils;`
`3`	`4`	`import com.fishercoder.solutions._435;`
`4`	`5`	`import org.junit.BeforeClass;`
`5`	`6`	`import org.junit.Test;`
`@@ -16,8 +17,8 @@ public static void setup() {`
`16`	`17`
`17`	`18`	`@Test`
`18`	`19`	`public void test1() {`
`19`		`- int[][] intervals = new int[][]{new int[]{1, 100}, new int[]{11, 22}, new int[]{1, 11}, new int[]{2, 12}};`
`20`		`- assertEquals(2, solution1.eraseOverlapIntervals(intervals));`
	`20`	`+ int[][] intervals = CommonUtils.convertLeetCodeIrregularLengths2DArrayInputIntoJavaArray("[1,2],[2,3],[3,4],[1,3]");`
	`21`	`+ assertEquals(1, solution1.eraseOverlapIntervals(intervals));`
`21`	`22`	`}`
`22`	`23`
`23`	`24`	`}`