面试题 3.1：找出数组中重复的数字

03_01_FindDuplication.cpp

bool duplicate(int numbers[], int length, int *duplication) {
    if(numbers == nullptr || length <= 0) {
        return false;
    }
    for(int i = 0; i < length; ++i) {
        if(numbers[i] < 0 || numbers[i] > length-1) {
            return false;
        }
    }
    for(int i = 0; i < length; ++i) {
        while(numbers[i] != i) {
            if(numbers[i] == numbers[numbers[i]]) {
                *duplication = numbers[i];
                return true;
            }
            int temp = numbers[i];
            numbers[i] = numbers[temp];
            numbers[temp] = temp;
        }
    }
    return false;
}