435 java solution

java/435-Non-Overlapping-Intervals.java

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+public class Solution {
+ public int eraseOverlapIntervals(int[][] intervals) {
+ int intervalsRemoved = 0;
+
+ //sort by the first vale in the intervals least to greatest
+ Arrays.sort(intervals, (arr1,arr2) -> Integer.compare(arr1[0], arr2[0]));
+ System.out.println(Arrays.deepToString(intervals));
+
+ //get the first interval
+ int[] intervalFirst = intervals[0];
+
+ // then loop through the rest of the intervals
+ for(int i = 1; i < intervals.length; i++){
+ if(firstIntervalwithinSecond(intervalFirst, intervals[i])){
+ //mark first interval to be removed
+ intervalsRemoved++;
+ // determine which interval to remove
+ //remove the interval that ends last
+ if(intervalFirst[1] > intervals[i][1]){
+ intervalFirst = intervals[i];
+ }
+ } else { 
+ intervalFirst = intervals[i];
+ }
+ }
+ return intervalsRemoved;
+ }
+
+ public boolean firstIntervalwithinSecond(int[] intervalFirst, int[] intervalSecond){
+ return intervalSecond[0] < intervalFirst[1];
+ }
+}