The algorithm cannot get the best diff results？

If I have two arrays like below:
```
A: [a, b, c]
B: [b, c, a]
```
the diff result will be:
```
[
(source:1, target:0),
(source:2,target:1)
]
```
In fact, we just need 1 move:
```
(source:0, target 2)
```

Is this algorithm not able to get best diff results?