import java.util.*; class Solution { public int solution(String[][] book_time) { inputArrayList(book_time); Collections.sort(Arr); // System.out.println(Arr); for(int e : Arr){ for(int i=0; i<1000; i++){ if(times[i] <= getStartTime(e)){ times[i] = getEndTime(e) + 10; break; } } } int cnt = 0; for(; cnt<1000 && times[cnt]>0; cnt++); return cnt; } static ArrayList Arr = new ArrayList<>(); static int[] times = new int[1000]; public static void inputArrayList(String[][] arr){ for(String[] e : arr){ Arr.add(intValueOfTime(e[0]) * 10000 + intValueOfTime(e[1])); } } public static int intValueOfTime(String str){ StringTokenizer st = new StringTokenizer(str,":"); int H = Integer.parseInt(st.nextToken()); int M = Integer.parseInt(st.nextToken()); return H*60 + M; } public static int getStartTime(int n){ return n/10000; } public static int getEndTime(int n){ return n%10000; } }