670. Maximum Swap¶

Difficulty: Medium

670. Maximum Swap

Medium

You are given an integer num. You can swap two digits at most once to get the maximum valued number.

Return the maximum valued number you can get.

Example 1:

Input: num = 2736
Output: 7236
Explanation: Swap the number 2 and the number 7.

Example 2:

Input: num = 9973
Output: 9973
Explanation: No swap.

Constraints:

0 <= num <= 10⁸

Solution¶

class Solution {
    public int maximumSwap(int num) {
        char[] digits = Integer.toString(num).toCharArray();
        int[] arr = new int[10];
        for (int i = 0; i < digits.length; i++) arr[digits[i] - '0'] = i;
        for (int i = 0; i < digits.length; i++) {
            for (int k = 9; k > digits[i] - '0'; k--) {
                if (arr[k] > i) {
                    char tmp = digits[i];
                    digits[i] = digits[arr[k]];
                    digits[arr[k]] = tmp;
                    return Integer.valueOf(new String(digits));
                }
            }
        }
        return num;
    }
}

Complexity Analysis¶

Time Complexity: O(?)
Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here