Created
September 6, 2017 04:24
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[ReverseArray] #practice
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class ReverseArray { | |
/* | |
Input: str = "a,b$c" | |
Output: str = "c,b$a" | |
Note that $ and , are not moved anywhere. | |
Only subsequence "abc" is reversed | |
Input: str = "Ab,c,de!$" | |
Output: str = "ed,c,bA!$" | |
*/ | |
static void main(String[] args) { | |
println reverse('a,b$c') | |
println reverse('Ab,c,de!$') | |
} | |
static String reverse(String input) { | |
char[] arr = input.toCharArray() | |
int i = 0, j = arr.length | |
if (j % 2 == 0) { | |
j = j / 2 | |
} else { | |
j = (j - 1) / 2 | |
} | |
int k = arr.length - 1 | |
while (k > j) { | |
if (!swappable(arr[i])) { | |
i++ | |
} | |
if (!swappable(arr[k])) { | |
k-- | |
} | |
if (swappable(arr[i]) && swappable(arr[k])) { | |
Character temp = arr[k] | |
arr[k] = arr[i] | |
arr[i] = temp | |
i++ | |
k-- | |
} | |
} | |
arr.toString() | |
} | |
static boolean swappable(Character c) { | |
return c.toString() ==~ /[A-Za-z0-9]/ | |
} | |
} |
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