Checking if two strings are permutations of each other

Question

How to determine if two strings are permutations of each other

Answer 1

I'm working on a Java library that should simplify your task. You can re-implement this algorithm using only two method calls:

boolean arePermutationsOfSameString(String s1, String s2) {
    s1 = $(s1).sort().join(); 
    s2 = $(s2).sort().join();
    return s1.equals(s2);
}

testcase

@Test
public void stringPermutationCheck() {
    // true cases
    assertThat(arePermutationsOfSameString("abc", "acb"), is(true));
    assertThat(arePermutationsOfSameString("bac", "bca"), is(true));
    assertThat(arePermutationsOfSameString("cab", "cba"), is(true));

    // false cases
    assertThat(arePermutationsOfSameString("cab", "acba"), is(false));
    assertThat(arePermutationsOfSameString("cab", "acbb"), is(false));

    // corner cases
    assertThat(arePermutationsOfSameString("", ""), is(true));
    assertThat(arePermutationsOfSameString("", null), is(true));
    assertThat(arePermutationsOfSameString(null, ""), is(true));
    assertThat(arePermutationsOfSameString(null, null), is(true));
}

PS

In the case you can clone the souces at bitbucket.