@@ -2,54 +2,34 @@ use crate::q::Solution;
22
33#[ allow( unused) ]
44impl Solution {
5- // 给定两个由小写字母构成的字符串 A 和 B ,只要我们可以通过交换 A 中的两个字母得到与 B 相等的结果,就返回 true ;否则返回 false 。
6- // 0 <= A.length <= 20000
7- // 0 <= B.length <= 20000
8- // A 和 B 仅由小写字母构成。
9- pub fn buddy_strings ( a : String , b : String ) -> bool {
10- if a. len ( ) != b. len ( ) {
11- return false ;
5+ pub fn buddy_strings ( s : String , goal : String ) -> bool {
6+ // 方法1
7+ // 交换一次的情况下要相等
8+ // 1. 那么首先要保证的就是两个字符串的长度要相等
9+ // 2. 然后两个字符串的字符频率要一样
10+ // 3. 接着检查两个字符串的对位不相同的字符数量是否为2或者没有
11+ // 3.1 如果为2,那一定可以交换
12+ // 3.2 如果没有,那么就要判断是否至少有一个字符的频率要大于等于2(至少2个才可以交换)
13+ // AC 0ms 2.2mb 34/34
14+ let s: Vec < char > = s. chars ( ) . collect ( ) ;
15+ let goal: Vec < char > = goal. chars ( ) . collect ( ) ;
16+ if s. len ( ) != goal. len ( ) { return false ; }
17+ let mut diff = 0 ;
18+ let mut freq_s = vec ! [ 0 ; 26 ] ;
19+ let mut freq_goal = vec ! [ 0 ; 26 ] ;
20+ for i in 0 ..s. len ( ) {
21+ if s[ i] != goal[ i] { diff += 1 ; }
22+ freq_s[ ( s[ i] as u8 - b'a' ) as usize ] += 1 ;
23+ freq_goal[ ( goal[ i] as u8 - b'a' ) as usize ] += 1 ;
1224 }
13- let mut buckets = vec ! [ 0 ; 256 ] ;
14- let a = a. chars ( ) . collect :: < Vec < char > > ( ) ;
15- let b = b. chars ( ) . collect :: < Vec < char > > ( ) ;
16- let mut swap = ( 0 , 0 ) ;
17- let mut count = 0 ;
18- for i in 0 ..a. len ( ) {
19- let ch1 = a[ i] as u8 ;
20- let ch2 = b[ i] as u8 ;
21- buckets[ ch1 as usize ] += 1 ;
22- 23- if ch1 != ch2 {
24- if count > 2 {
25- return false ;
26- }
27- if count == 0 {
28- swap. 0 = ch1;
29- swap. 1 = ch2;
30- } else if swap. 0 != ch2 || swap. 1 != ch1 {
31- return false ;
32- }
33- count += 1 ;
34- }
25+ for i in 0 ..26 {
26+ if freq_s[ i] != freq_goal[ i] { return false ; }
3527 }
36- if count == 0 {
37- for i in 0 ..256 {
38- if buckets[ i] > 1 {
39- return true ;
40- }
28+ if diff == 0 {
29+ for i in 0 ..26 {
30+ if freq_s[ i] > 1 { return true ; }
4131 }
4232 }
43- count != 0
33+ diff == 2
4434 }
45- }
46- 47- #[ test]
48- fn test_q859 ( ) {
49- assert_eq ! ( true , Solution :: buddy_strings( "ba" . to_string( ) , "ab" . to_string( ) ) ) ;
50- assert_eq ! ( false , Solution :: buddy_strings( "ab" . to_string( ) , "ab" . to_string( ) ) ) ;
51- assert_eq ! ( false , Solution :: buddy_strings( "abc" . to_string( ) , "abc" . to_string( ) ) ) ;
52- assert_eq ! ( false , Solution :: buddy_strings( "abcd" . to_string( ) , "abcd" . to_string( ) ) ) ;
53- assert_eq ! ( true , Solution :: buddy_strings( "aba" . to_string( ) , "aba" . to_string( ) ) ) ;
54- assert_eq ! ( true , Solution :: buddy_strings( "aa" . to_string( ) , "aa" . to_string( ) ) ) ;
5535}
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