# 2158. Amount of New Area Painted Each Day
###### tags: `Leetcode` `Hard` `Merge Interval`
Link: https://leetcode.com/problems/amount-of-new-area-painted-each-day/
## 思路
思路[参考](https://leetcode.com/problems/amount-of-new-area-painted-each-day/discuss/1751389/Jump-Line)
compress path的概念
For a day ```i```, try painting all areas in the range.
- If the area is empty, set the value on the number line to ```end_i```, and increment the amount painted on that day.
- If the area has been painted previously, jump to the end of the painted range (which was recorded on the number line on a previous day).
## Code

class Solution {
    public int[] amountPainted(int[][] paint) {
        int[] line = new int[50001];
        int n = paint.length;
        int[] ans = new int[n];
        for(int i=0; i<n; i++){
            int start = paint[i][0];
            int end = paint[i][1];
            int p = 0;
            while(start<end){
                int jump = Math.max(start+1, line[start]);
                if(line[start]==0) ans[i]++;
                line[start] = Math.max(end, line[start]);
                start = jump;
            }
        }
        return ans;
    }
}