C 解法, 执行用时: 1ms, 内存消耗: 272KB, 提交时间: 2020-10-29

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <limits.h>



int main()
{
	/* 初始化对照表 */
	char sAlphabet[26] = { 0 };
	char cBegin = 'A';
	for (int i = 0; i < 26; i++)
	{
		sAlphabet[i] = cBegin;
		cBegin++;
	}


	char sInWord[100] = { 0 };
	char sText[100] = { 0 };
	while (scanf("%s%s", sInWord, sText) != EOF)
	{
			char sKeyUp[26] = { 0 };
			char sKeyDown[26] = { 0 };
			char sUpInWorf[100] = { 0 };
			/* 输入单词转大写 */
			for (int i = 0; i < strlen(sInWord); i++)
			{
				if (sInWord[i] >= 'a' && sInWord[i] <= 'z')
				{
					sUpInWorf[i] = sInWord[i] - 32;
				}
			}
			/* 单词去重 */
			char sOutWord[26] = { 0 };
			int iCount = 0;
			for (int j = 0; j < strlen(sUpInWorf); j++)
			{
				if (strchr(sOutWord, sUpInWorf[j]) == NULL)
				{
					sOutWord[iCount] = sUpInWorf[j];
					iCount++;
				}
			}

			/* 生成单词表 */
			sprintf(sKeyUp, "%s", sOutWord);
			for (int i = 0; i < 26; i++)
			{
				if (strchr(sKeyUp, sAlphabet[i]) == NULL)
				{
					sKeyUp[iCount] = sAlphabet[i];
					iCount++;
				}
			}

			/* 对照生成小写密码表 */
			for (int i = 0; i < 26; i++)
			{
				sKeyDown[i] = sKeyUp[i] + 32;
			}

			/* 转换 */
			for (int k = 0; k < strlen(sText); k++)
			{
				if (sText[k] >= 'a' && sText[k] <= 'z')
				{
					printf("%c", sKeyDown[sText[k] - 'a']);
				}
				else if (sText[k] >= 'A' && sText[k] <= 'Z')
				{
					printf("%c", sKeyUp[sText[k] - 'A']);
				}
			}
			printf("\n");
	}

	return 0;
}

C 解法, 执行用时: 1ms, 内存消耗: 356KB, 提交时间: 2021-07-31

#include <stdio.h>

int main(void)
{
    char key[1000], *pKey;
    
    while(scanf("%s", &key[0]) != EOF)
    {
        char alpbat[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        char decrypt[26] = {0};
        int decrypt_len = 0;
        short cnt[128] = {0};
        pKey = key;
        
        char info[1000], *pInfo;
        scanf("%s", &info[0]);
        pInfo = info;
        
//         printf("%s\n", pKey);
//         printf("%s\n", pInfo);
        
        for(;*pKey;pKey++)
        {
            if(*pKey >= 'a' && *pKey <= 'z')
            {
                *pKey -= ('a' - 'A');
            }
            
            if(!cnt[*pKey])
            {
                cnt[*pKey]++;
                decrypt[decrypt_len++] = *pKey;
                alpbat[*pKey - 'A'] = 0;
            }
        }
        decrypt[decrypt_len] = '\0';
        
//         printf("%s\n", alpbat);
//         printf("%s\n", decrypt);
        
        for(int i = 0;i < 26;i++)
        {
            if(alpbat[i])
            {
                decrypt[decrypt_len++] = alpbat[i];
            }
        }
         decrypt[decrypt_len] = '\0';
        
//         printf("%s\n", alpbat);
//         printf("%s\n", decrypt);
        
        for(;*pInfo;pInfo++)
        {
            if(*pInfo >= 'a' && *pInfo <= 'z')
                printf("%c", decrypt[*pInfo - 'a'] + 'a' - 'A');
            else if(*pInfo >= 'A' && *pInfo <= 'Z')
                printf("%c", decrypt[*pInfo - 'A']);
        }
        printf("\n");
    }
    return 0;
}