715. Range Module

区间模块设计与实现

最新推荐文章于 2024-09-24 18:49:27 发布

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本文介绍了一种区间模块的设计与实现方法，通过使用TreeMap来高效地完成区间添加、查询和删除的操作。提供了完整的代码实现及说明。

715. Range Module

题目描述：A Range Module is a module that tracks ranges of numbers. Your task is to design and implement the following interfaces in an efficient manner.

addRange(int left, int right) Adds the half-open interval [left, right), tracking every real number in that interval. Adding an interval that partially overlaps with currently tracked numbers should add any numbers in the interval [left, right) that are not already tracked.

queryRange(int left, int right) Returns true if and only if every real number in the interval [left, right) is currently being tracked.

removeRange(int left, int right) Stops tracking every real number currently being tracked in the interval [left, right).
题目大意：实现一个区间模型，可以实现插入，查询，删除区间的功能。
思路：使用treemap会对键值对升序排序的特征完成功能。

代码:

class RangeModule {
      TreeMap<Integer, Integer> map;
      public RangeModule() {
          map = new TreeMap<>();
      }

      public void addRange(int left, int right) {
          if (right <= left) {
              return;
          }
          Integer start = map.floorKey(left);
          Integer end = map.floorKey(right);
//            如果当前的区间不存在重合的部分
          if (start == null && end == null) {
              map.put(left, right);
          } else if (start != null && map.get(start) >= left) {
              map.put(start, Math.max(map.get(end), Math.max(map.get(start), right)));
          } else {
              map.put(left, Math.max(map.get(end), right));
          }
          Map<Integer, Integer> subMap = map.subMap(left, false, right, true);
          Set<Integer> set = new HashSet<>(subMap.keySet());
          map.keySet().removeAll(set);
      }

      public boolean queryRange(int left, int right) {
          Integer start = map.floorKey(left);
          if (start == null) return false;
          return map.get(start) >= right;
      }

      public void removeRange(int left, int right) {
          if (right <= left) {
              return;
          }
          Integer start = map.floorKey(left);
          Integer end = map.floorKey(right);
          if (end != null && map.get(end) > right) {
              map.put(right, map.get(end));
          }
          if (start != null && map.get(start) > left) {
              map.put(start, left);
          }
          // clean up intermediate intervals
          Map<Integer, Integer> subMap = map.subMap(left, true, right, false);
          Set<Integer> set = new HashSet(subMap.keySet());
          map.keySet().removeAll(set);
      }
  }

/**
* Your RangeModule object will be instantiated and called as such:
* RangeModule obj = new RangeModule();
* obj.addRange(left,right);
* boolean param_2 = obj.queryRange(left,right);
* obj.removeRange(left,right);
*/