1893. 检查是否区域内所有整数都被覆盖

题目链接:https://leetcode.cn/problems/check-if-all-the-integers-in-a-range-are-covered/

class Solution {
public:
    bool isCovered(vector<vector<int>>& ranges, int left, int right) {
        vector<int> sum(55,0); //sum就是差分数组

        for(int i = 0;i < ranges.size();i ++)
        {
            int l = ranges[i][0],r = ranges[i][1];
            sum[l] ++,sum[r + 1] --;
        }
        for(int i = 1;i < 51;i ++) sum[i] += sum[i - 1];
        for(int i = left;i <= right;i ++)
        {
            if(sum[i] < 1)
            {
                return false;
            }
        }

        return 1;

    }
};