1024_100_100

class Solution {
public:
    int videoStitching(vector<vector<int>>& clips, int T) {
        int s = 0;
        int bn = 0;
        int num = 0;
        int right = 0;
        while(right < T){
            for(auto i:clips){
                if(i[0] <= right && i[1] > right && i[1] > bn){
                    bn = i[1];
                }
            }
            if(right == bn)
                break;
            right = bn;
            num ++;
        }
        if (right>=T)
            return num;
        else
            return -1;
    }
};