第四题求最多末尾0，感觉思路没问题，只过了4.5%，不知道哪错了 public class Main { private static int res = 0; public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); int[][] help = new int[n][2]; for(int i=0;i<n;i++){ int num = sc.nextInt(); while(num%5 == 0){ help[i][0]++; num /= 5; } while(num%2 == 0){ help[i][1]++; num /= 2; } } backTrack(0,help,0,0,true); System.out.println(res); } private static void backTrack(int i,int[][]help,int num5,int num2,boolean canTake){ if(i == help.length){ res = Math.max(res,Math.min(num2,num5)); return; } backTrack(i+1,help,num2,num5,true); if(canTake){ backTrack(i+1,help,num5+help[i][0],num2+help[i][1],false); } } }