Vigenère 密码题解

NOIP2012提高组第一题，博主一看到之后，就想到了使用用打表打运算规则，然后直接过。

额，题意博主就不再解释了，而且方法也不怎么难，也就不细说了。

直接上代码：

#include
#include
#include
#include
#include
#include

using namespace std;

char map[30][30] = {
{'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'},
{'b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a'},
{'c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b'},
{'d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c'},
{'e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d'},
{'f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e'},
{'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f'},
{'h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g'},
{'i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h'},
{'j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i'},
{'k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j'},
{'l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k'},
{'m','n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l'},
{'n','o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m'},
{'o','p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n'},
{'p','q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o'},
{'q','r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p'},
{'r','s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q'},
{'s','t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r'},
{'t','u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s'},
{'u','v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t'},
{'v','w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u'},
{'w','x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v'},
{'x','y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w'},
{'y','z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x'},
{'z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y'}};
char f1[10100], f2[10010];

int main() {
	int n, m, j, k, i;
	scanf("%s", &f1);
	scanf("%s", &f2);
	int len1 = strlen(f1);
	int len2 = strlen(f2);
	for(i = 0;i < len1; ++i) 
		if(f1[i] >= 'A' && f1[i] <= 'Z')
			f1[i] = f1[i] - 'A' + 'a';
	i = 0;
	j = 0;
	int c1, c2;
	while(j <= len2) {
		if(f2[j] >= 'A' && f2[j] <= 'Z')
			c1 = f2[j] - 'A';	
		else
			c1 = f2[j] - 'a'; 
		c2 = f1[i] - 'a';
		if(f2[j] >= 'A' && f2[j] <= 'Z') {
			for(k = 0;k < 26; ++k)
				if(map[c2][k] == c1 + 'a') {
					printf("%c", k + 'A');
					break;
				}
		}
		else {
			for(k = 0;k < 26; ++k)
				if(map[c2][k] == c1 + 'a') {
					printf("%c", k + 'a');
					break;
				}
		}
		if(i == len1 - 1)
			i = -1; 
		++i;++j;
	}
	puts("");
	return 0;
}

主函数也就是：

首先变小写，接下来枚举就没有了……

额，就这样，呵呵。