[搜狗] 找一个字符串中包含全部出现字符的最小字符串

一个字符串中含有n个字符，其中有m个不同的字符，n>>m，用最少的时间和空间找到包含所有这m个字符的最短的字串，不考虑特殊字符，只考虑字母数字即可。
例如：

abccbaddac,返回：cbad

aabcadbbbcca，返回：bcad

实现代码：

#include <iostream>
using namespace std;
void Search(char input[], char output[]);
int main()
{
char* input = "abccbaddac";
char* output = new char[strlen(input)];
Search(input,output);
cout<<output<<endl;
}

void Search(char input[], char output[])
{
bool num[10] = {0}; //数字字符
bool small[26] = {0}; //小写字符
bool big[26] = {0}; //大写字符
int sum = 0; //不同字符的个数
int temp, index;
for (int i = 0; i < strlen(input); i++)
{
temp = input[i];
if (temp >= 97)
{
index = input[i] - 'a';
if (small[index] == 0)
{
small[index] = 1;
sum++;
}
}
else if (temp <= 57)
{
index = input[i] - '0';
if (num[index] == 0)
{
num[index] = 1;
sum++;
}
}
else
{
index = input[i] - 'A';
if (big[index] == 0)
{
big[index] = 1;
sum++;
}
}
}

bool t_num[10] = {0}; //数字字符
bool t_small[26] = {0}; //小写字符
bool t_big[26] = {0}; //大写字符
int t_sum = 0;

int min = strlen(input);
char* out = new char[strlen(output) + 1];
memset(out,0,sizeof(out));

for (int i = 0; i < strlen(input); i++)
{
char* pout = out;
t_sum = 0;
memset(t_num,0,sizeof(t_num));
memset(t_small,0,sizeof(t_small));
memset(t_big,0,sizeof(t_big));
int j = i;
while(j < strlen(input))
{
*pout++ = input[j];
temp = input[j];
if (temp >= 97)
{
index = input[j] - 'a';
if (t_small[index] == 0)
{
t_small[index] = 1;
t_sum++;
}
}
else if (temp <= 57)
{
index = input[j] - '0';
if (t_num[index] == 0)
{
t_num[index] = 1;
t_sum++;
}
}
else
{
index = input[j] - 'A';
if (t_big[index] == 0)
{
t_big[index] = 1;
t_sum++;
}
}
if (t_sum == sum)
{
int len = j - i;
if(min > len)
{
min = len;
*pout = '\0';
strcpy(output,out);
j = i + len - sum;
break;
}
}
j++;
}
}
delete [] out;
}