35. 无重叠区间

题目链接：435. 无重叠区间 - 力扣（LeetCode）

class Solution {public int eraseOverlapIntervals(int[][] intervals) {Arrays.sort(intervals, (x1, x2) -> {if (x1[0] != x2[0]) {return x1[0] - x2[0];} else {return x1[1] - x2[1];}});int ret = 0;for(int i = 0; i < intervals.length - 1; ++i) {if(intervals[i][1] > intervals[i+1][0]) {intervals[i + 1][1] = Math.min(intervals[i][1], intervals[i+1][1]);ret++;}}return ret;}
}

763.划分字母区间

题目链接：763. 划分字母区间 - 力扣（LeetCode）

class Solution {public List<Integer> partitionLabels(String s) {int[] a = new int[26];int[] b = new int[26];for(int i = 0; i < s.length(); ++i) {++a[s.charAt(i)-'a'];}List<Integer> ans = new ArrayList<>();int differ = 0, len = 0;for(int i = 0; i < s.length(); ++i) {++len;int index = s.charAt(i) - 'a';++b[index];if(b[index] == 1) {++differ;}if(b[index] == a[index]) {--differ;}if(differ == 0) {ans.add(len);len = 0;}}return ans; }
}

56. 合并区间

题目链接：56. 合并区间 - 力扣（LeetCode）

class Solution {public int[][] merge(int[][] intervals) {Arrays.sort(intervals, new Comparator<int[]>() {public int compare(int[] a,int[] b){return a[0] - b[0];}});List<int []> list = new ArrayList<>();for(int i = 0; i < intervals.length; ++i) {int L = intervals[i][0], R = intervals[i][1];if(list.isEmpty() || list.get(list.size()-1)[1] < L) {list.add(intervals[i]);}else {list.get(list.size()-1)[1] = Math.max(list.get(list.size()-1)[1], R);}}return list.toArray(new int[list.size()][]);}
}