LeetCode-in-Java

1893. Check if All the Integers in a Range Are Covered

Easy

You are given a 2D integer array ranges and two integers left and right. Each ranges[i] = [starti, endi] represents an inclusive interval between starti and endi.

Return true if each integer in the inclusive range [left, right] is covered by at least one interval in ranges. Return false otherwise.

An integer x is covered by an interval ranges[i] = [starti, endi] if starti <= x <= endi.

Example 1:

Input: ranges = [[1,2],[3,4],[5,6]], left = 2, right = 5

Output: true

Explanation: Every integer between 2 and 5 is covered:

• 2 is covered by the first range.

• 3 and 4 are covered by the second range.

• 5 is covered by the third range.

Example 2:

Input: ranges = [[1,10],[10,20]], left = 21, right = 21

Output: false

Explanation: 21 is not covered by any range.

Constraints:

• 1 <= ranges.length <= 50
• 1 <= starti <= endi <= 50
• 1 <= left <= right <= 50

Solution

public class Solution {
    public boolean isCovered(int[][] ranges, int left, int right) {
        int[] temp = new int[52];
        for (int[] range : ranges) {
            int start = range[0];
            int end = range[ranges[0].length - 1];
            temp[start] += 1;
            temp[end + 1] += -1;
        }
        for (int i = 1; i < temp.length; i++) {
            temp[i] += temp[i - 1];
        }
        for (int i = left; i <= right; i++) {
            if (temp[i] == 0) {
                return false;
            }
        }
        return true;
    }
}

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