Count the Colors
Description
Painting some colored segments on a line, some previously painted segments may be covered by some the subsequent ones.
Your task is counting the segments of different colors you can see at last.
Input
The first line of each data set contains exactly one integer n, 1 <= n <= 8000, equal to the number of colored segments.
Each of the following n lines consists of exactly 3 nonnegative integers separated by single spaces:
x1 x2 c
x1 and x2 indicate the left endpoint and right endpoint of the segment, c indicates the color of the segment.
All the numbers are in the range [0, 8000], and they are all integers.
Input may contain several data set, process to the end of file.
Output
Each line of the output should contain a color index that can be seen from the top, following the count of the segments of this color, they should be printed according to the color index.
If some color can't be seen, you shouldn't print it.
Print a blank line after every dataset.
Sample Input
5
0 4 4
0 3 1
3 4 2
0 2 2
0 2 3
4
0 1 1
3 4 1
1 3 2
1 3 1
6
0 1 0
1 2 1
2 3 1
1 2 0
2 3 0
1 2 1
Sample Output
1 1
2 1
3 1
1 1
0 2
1 1
大意:为线段上的子线段涂不同颜色的色块,新涂的会覆盖掉旧的。对应于涂色过程的输入为每行三个整数 x1 x2 c ,代表线段中本次涂色的子线段的起点与终点。问到最后每种颜色各有多少块。
分析:将整个线段分割成单位长度为1的子线段。以数组color[i]表示(i,i+1)区间上的色块颜色(从0开始记)。每次涂色,都要修改一个区间,所以用线段树来维护区间信息。