# 1893. Check if All the Integers in a Range Are Covered
###### tags: `Leetcode` `Easy` `Line Sweep`
Link: https://leetcode.com/problems/check-if-all-the-integers-in-a-range-are-covered/
## 思路 $O(N)$ $O(1)$
## Code

class Solution {
    public boolean isCovered(int[][] ranges, int left, int right) {
        int[] line = new int[52];
        for(int[] range: ranges){
            line[range[0]] += 1;
            line[range[1]+1] -= 1;
        }
        int overlap = 0;
        for(int i=0; i<=right; i++){
            overlap += line[i];
            if(i>=left && overlap==0) return false;
        }
        return true;
    }
}