LeetCode 715. Range Module Range 模块 (Java)

题目：

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).

Example 1:

addRange(10, 20): null
removeRange(14, 16): null
queryRange(10, 14): true (Every number in [10, 14) is being tracked)
queryRange(13, 15): false (Numbers like 14, 14.03, 14.17 in [13, 15) are not being tracked)
queryRange(16, 17): true (The number 16 in [16, 17) is still being tracked, despite the remove operation)

 

Note:

• A half open interval [left, right) denotes all real numbers left <= x < right.
• 0 < left < right < 10^9 in all calls to addRange, queryRange, removeRange.
• The total number of calls to addRange in a single test case is at most 1000.
• The total number of calls to queryRange in a single test case is at most 5000.
• The total number of calls to removeRange in a single test case is at most 1000.

分析：

维护一个区间集合，支持增加和删除区间的操作，当queryRange也就是查询某个区间是否存在时，如果是已有区间包含查询的区间就返回true。

使用一个List用来存储所有的区间，在add方法中保持List中的区间有序。每一次add新区间时，都遍历原来的List，找到待添加区间应插入的位置。

如果原来的区间和插入区间有重叠，就将它们合并。

查询区间可以通过二分法来查找。

程序：

class RangeModule {

    public RangeModule() {
        range = new LinkedList<>();
    }
    
    public void addRange(int left, int right) {
        List<int[]> tempList = new LinkedList<>();
        boolean insert = false;
        for(int[] r:range){
            if(right < r[0] && !insert){
                tempList.add(new int[]{left, right});
                insert = true;
            }
            if(r[0] > right ||r[1] < left)
                tempList.add(r);
            else{
                left = Math.min(left, r[0]);
                right = Math.max(right, r[1]);
            }
        }
        if(!insert)
            tempList.add(new int[]{left, right});
        range = tempList;
    }
    
    public boolean queryRange(int left, int right) {
        int l = 0;
        int r = range.size()-1;
        while(l <= r){
            int mid = l + (r - l) / 2;
            int[] p = range.get(mid);
            if(right < p[0]){
                r = mid - 1;
            }else if(p[1] < left){
                l = mid + 1;
            }else{
                return p[0] <= left && p[1] >= right;
            }
        }
        return false;
    }
    
    public void removeRange(int left, int right) {
        List<int[]> tempList = new LinkedList<>();
        for(int[] r:range){
            if(r[0] > right || r[1] < left)
                tempList.add(r);
            else{
                if(r[0] < left)
                    tempList.add(new int[]{r[0], left});
                if(r[1] > right)
                    tempList.add(new int[]{right, r[1]});
            }
        }
        range = tempList;
    }
    private List<int[]> range;
}

/**
 * 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);
 */