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/*******************************************************************
Copyright(c) 2016, Harry He
All rights reserved.
Distributed under the BSD license.
(See accompanying file LICENSE.txt at
https://github.com/zhedahht/CodingInterviewChinese2/blob/master/LICENSE.txt)
*******************************************************************/
//==================================================================
// 《剑指Offer——名企面试官精讲典型编程题》代码
// 作者:何海涛
//==================================================================
// 面试题3(一):找出数组中重复的数字
// 题目:在一个长度为n的数组里的所有数字都在0到n-1的范围内。数组中某些数字是重复的,但不知道有几个数字重复了,
// 也不知道每个数字重复了几次。请找出数组中任意一个重复的数字。例如,如果输入长度为7的数组{2, 3, 1, 0, 2, 5, 3},
// 那么对应的输出是重复的数字2或者3。
#include <cstdio>
// 参数:
// numbers: 一个整数数组
// length: 数组的长度
// duplication: (输出) 数组中的一个重复的数字
// 返回值:
// true - 输入有效,并且数组中存在重复的数字
// false - 输入无效,或者数组中没有重复的数字
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;
}
// 交换numbers[i]和numbers[numbers[i]]
int temp = numbers[i];
numbers[i] = numbers[temp];
numbers[temp] = temp;
}
}
return false;
}
// ====================测试代码====================
bool contains(int array[], int length, int number)
{
for(int i = 0; i < length; ++i)
{
if(array[i] == number)
return true;
}
return false;
}
void test(char* testName, int numbers[], int lengthNumbers, int expected[], int expectedExpected, bool validArgument)
{
printf("%s begins: ", testName);
int duplication;
bool validInput = duplicate(numbers, lengthNumbers, &duplication);
if(validArgument == validInput)
{
if(validArgument)
{
if(contains(expected, expectedExpected, duplication))
printf("Passed.\n");
else
printf("FAILED.\n");
}
else
printf("Passed.\n");
}
else
printf("FAILED.\n");
}
// 重复的数字是数组中最小的数字
void test1()
{
int numbers[] = { 2, 1, 3, 1, 4 };
int duplications[] = { 1 };
test("Test1", numbers, sizeof(numbers) / sizeof(int), duplications, sizeof(duplications) / sizeof(int), true);
}
// 重复的数字是数组中最大的数字
void test2()
{
int numbers[] = { 2, 4, 3, 1, 4 };
int duplications[] = { 4 };
test("Test2", numbers, sizeof(numbers) / sizeof(int), duplications, sizeof(duplications) / sizeof(int), true);
}
// 数组中存在多个重复的数字
void test3()
{
int numbers[] = { 2, 4, 2, 1, 4 };
int duplications[] = { 2, 4 };
test("Test3", numbers, sizeof(numbers) / sizeof(int), duplications, sizeof(duplications) / sizeof(int), true);
}
// 没有重复的数字
void test4()
{
int numbers[] = { 2, 1, 3, 0, 4 };
int duplications[] = { -1 }; // not in use in the test function
test("Test4", numbers, sizeof(numbers) / sizeof(int), duplications, sizeof(duplications) / sizeof(int), false);
}
// 没有重复的数字
void test5()
{
int numbers[] = { 2, 1, 3, 5, 4 };
int duplications[] = { -1 }; // not in use in the test function
test("Test5", numbers, sizeof(numbers) / sizeof(int), duplications, sizeof(duplications) / sizeof(int), false);
}
// 无效的输入
void test6()
{
int* numbers = nullptr;
int duplications[] = { -1 }; // not in use in the test function
test("Test6", numbers, 0, duplications, sizeof(duplications) / sizeof(int), false);
}
void main()
{
test1();
test2();
test3();
test4();
test5();
test6();
}
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