chr1 :100-200
chr1 :50-150
chr10:20-30
chr3 :100-300
chrX :30-100
0: chr1 
1: chr10
2: chr3 
3: chrX 
0: chr1 
1: chr3 
2: chr10
3: chrX 

After sorting:

chr1 :50-200
chr3 :100-300
chr10:20-30
chrX :30-100
chr1:100-200
chr1:50-150
chr10:20-30
chr3:100-300
chrX:30-100
0: chr1
1: chr10
2: chr3
3: chrX
0: chr1
1: chr3
2: chr10
3: chrX

After sorting:

chr1:50-200
chr3:100-300
chr10:20-30
chrX:30-100
