670. Maximum Swap

670. Maximum Swap

Medium

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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

Accepted

158,888

Submissions

335,266

class Solution:
    def maximumSwap(self, num: int) -> int:
        D=list(str(num))
        dp=list(accumulate(D[::-1],max))[::-1]
        
        for i,digit in enumerate(D):
            if dp[i]>digit:
                for k in range(i+1,len(D)):
                    if D[k]==dp[i]:
                        j=k
                D[i],D[j]=D[j],D[i]
                return "".join(D)
        return num