CareerCup1.3.cpp

CareerCup1.3.cpp

/* Chapter 1
 * 1.3 Given two strings, write a method to decide if one is a permutation of the other.
 */

#include <iostream>
#include <string>

using namespace std;

bool permutation(char* str1, char* str2)
{
    if (strlen(str1) != strlen(str2)) {r
        eturn false;
    }
    else if (strlen(str1) == 0 && strlen(str2) == 0) {
        cout << "They're both empty string." << endl;
    }
    else {
        int counter[256];  // for extended ASCII
        memset(counter, 0, sizeof(counter)); // set counter to 0
        
        // Counter acts as indicator(elegant&efficient)
        // No need to initialize two different counter to record
        // then compare each slot's value
        for (int i = 0; i < strlen(str1); i++) {
            ++counter[(int)str1[i]];
            --counter[(int)str2[i]];
        }
        
        for (int i; i < 256; i++) {
            if (counter[i] != 0) {
                return false;
            }
        }
    }
    return true;
}
        
int main(int argc, char const *argv[])
{
    char str1[] = "mary";
    char str2[] = "army";
    cout << permutation(str1, str2) << endl;
    return 0;
}