Given two strings A and B of lowercase letters, return true if and only if we can swap two letters in A so that the result equals B.
Example 1:
Input: A = "ab", B = "ba"
Output: true
Example 2:
Input: A = "ab", B = "ab"
Output: false
Example 3:
Input: A = "aa", B = "aa"
Output: true
Example 4:
Input: A = "aaaaaaabc", B = "aaaaaaacb"
Output: true
Example 5:
Input: A = "", B = "aa"
Output: false
Note:
0 <= A.length <= 20000
0 <= B.length <= 20000
A and B consist only of lowercase letters.
难度: Medium
题目:给定两字符串A和B且由小写字线组成,返回AB是否由仅交换两个字符可以相互生成。
思路:判断长度,记录不同位置的个数,记录是否有相同的字符。
Runtime: 3 ms, faster than 81.94% of Java online submissions for Buddy Strings.
Memory Usage: 38.6 MB, less than 50.00% of Java online submissions for Buddy Strings.
class Solution {
public boolean buddyStrings(String A, String B) {
if (A.length() != B.length()) {
return false;
}
int[] tableA = new int[26];
int[] tableB = new int[26];
int diffPosition = 0;
for (int i = 0; i < A.length(); i++) {
char a = A.charAt(i);
char b = B.charAt(i);
if (a != b) {
diffPosition++;
}
if (diffPosition > 2) {
return false;
}
tableA[a - 'a']++;
tableB[b - 'a']++;
}
boolean duplicated = false;
for (int i = 0; !duplicated && i < 26; i++) {
if (tableA[i] != tableB[i]) {
return false;
}
duplicated = tableA[i] > 1 ? !duplicated : duplicated;
}
return 2 == diffPosition || duplicated;
}
}
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