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Formatted question description: https://leetcode.ca/all/1432.html
1432. Max Difference You Can Get From Changing an Integer
Level
Medium
Description
You are given an integer num
. You will apply the following steps exactly two times:
- Pick a digit
x (0 <= x <= 9)
. - Pick another digit
y (0 <= y <= 9)
. The digity
can be equal tox
. - Replace all the occurrences of
x
in the decimal representation ofnum
byy
. - The new integer cannot have any leading zeros, also the new integer cannot be 0.
Let a
and b
be the results of applying the operations to num
the first and second times, respectively.
Return the max difference between a
and b
.
Example 1:
Input: num = 555
Output: 888
Explanation: The first time pick x = 5 and y = 9 and store the new integer in a.
The second time pick x = 5 and y = 1 and store the new integer in b.
We have now a = 999 and b = 111 and max difference = 888
Example 2:
Input: num = 9
Output: 8
Explanation: The first time pick x = 9 and y = 9 and store the new integer in a.
The second time pick x = 9 and y = 1 and store the new integer in b.
We have now a = 9 and b = 1 and max difference = 8
Example 3:
Input: num = 123456
Output: 820000
Example 4:
Input: num = 10000
Output: 80000
Example 5:
Input: num = 9288
Output: 8700
Constraints:
1 <= num <= 10^8
Solution
Obviously, a
is the maximum possible integer and b
is the minimum possible integer.
To obtain a
, find the highest digit that is not 9, and replace all the digits with the value to 9.
To obtain b
, consider two cases.
- If the highest digit is 1, then find the highest digit that is not 0 or 1, and replace all the digits with the value to 0. Note that the original digit cannot have value 1 since the highest digit cannot be changed to 0.
- If the nighest digit is not 1, then simply replace all the digits with the same value as the highest digit to 1.
After obtaining a
and b
, return a - b
.
-
class Solution { public int maxDiff(int num) { int max = getMax(num), min = getMin(num); return max - min; } public int getMax(int num) { char[] array = String.valueOf(num).toCharArray(); int length = array.length; char original = '0'; for (int i = 0; i < length; i++) { if (array[i] != '9') { original = array[i]; break; } } for (int i = 0; i < length; i++) { if (array[i] == original) array[i] = '9'; } return Integer.parseInt(new String(array)); } public int getMin(int num) { char[] array = String.valueOf(num).toCharArray(); int length = array.length; if (array[0] == '1') { char original = '0'; for (int i = 1; i < length; i++) { if (array[i] != '0' && array[i] != '1') { original = array[i]; break; } } for (int i = 1; i < length; i++) { if (array[i] == original) array[i] = '0'; } } else { char original = array[0]; for (int i = 0; i < length; i++) { if (array[i] == original) array[i] = '1'; } } return Integer.parseInt(new String(array)); } }
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class Solution: def maxDiff(self, num: int) -> int: a, b = str(num), str(num) for c in a: if c != '9': a = a.replace(c, '9') break for i, c in enumerate(b): if i == 0: if c != '1': b = b.replace(c, '1') break else: if c != '0' and c != b[0]: b = b.replace(c, '0') break return int(a) - int(b) ############ class Solution: def maxDiff(self, num: int) -> int: replaces = [] num = str(num) for i in range(0, 10): for j in range(0, 10): rep_num = num.replace(str(i), str(j)) if rep_num[0] != '0': replaces.append(int(rep_num)) return max(replaces) - min(replaces)
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class Solution { public: int maxDiff(int num) { auto replace = [](string& s, char a, char b) { for (auto& c : s) { if (c == a) { c = b; } } }; string a = to_string(num); string b = a; for (int i = 0; i < a.size(); ++i) { if (a[i] != '9') { replace(a, a[i], '9'); break; } } if (b[0] != '1') { replace(b, b[0], '1'); } else { for (int i = 1; i < b.size(); ++i) { if (b[i] != '0' && b[i] != '1') { replace(b, b[i], '0'); break; } } } return stoi(a) - stoi(b); } };
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func maxDiff(num int) int { a, b := num, num s := strconv.Itoa(num) for i := range s { if s[i] != '9' { a, _ = strconv.Atoi(strings.ReplaceAll(s, string(s[i]), "9")) break } } if s[0] > '1' { b, _ = strconv.Atoi(strings.ReplaceAll(s, string(s[0]), "1")) } else { for i := 1; i < len(s); i++ { if s[i] != '0' && s[i] != '1' { b, _ = strconv.Atoi(strings.ReplaceAll(s, string(s[i]), "0")) break } } } return a - b }