2020-09-01
949. Largest Time for Given Digits
Question:
Given an array of 4 digits, return the largest 24 hour time that can be made.
The smallest 24 hour time is 00:00, and the largest is 23:59. Starting from 00:00, a time is larger if more time has elapsed since midnight.
Return the answer as a string of length 5. If no valid time can be made, return an empty string.
Example 1:
Input: [1,2,3,4]
Output: "23:41"
Example 2:
Input: [5,5,5,5]
Output: ""
Note:
A.length == 40 <= A[i] <= 9
Solution:
Enumerate each combination and find the max result with boundary check.
class Solution {
public String largestTimeFromDigits(int[] A) {
int result = -1;
for(int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
for (int k = 0; k < 4; k++) {
if (i == j || i == k || j == k) {
continue;
}
int h = A[i] * 10 + A[j];
int m = A[k] * 10 + A[6-i-j-k];
if (isValidTime(h, m)) {
result = Math.max(result, h * 60 + m);
}
}
}
}
if (result == -1){
return "";
}
return String.format("%02d:%02d", result / 60, result % 60);
}
private boolean isValidTime(int h, int m) {
if (h >= 0 && h <= 23 && m >= 0 && m <= 59) {
return true;
}
return false;
}
}