POJ1312(AC).cpp

#define _CRT_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

const int MAXN = 40;
char s[MAXN], s1[MAXN];
int a[MAXN];
int a0[MAXN];
int len;

void reverse(char s[])
{
	int i, len;
	char ch;

	i = 0;
	len = strlen(s);
	while(i < len - 1 - i){
		ch = s[i];
		s[i] = s[len - 1 - i];
		s[len - 1 - i] = ch;
		++i;
	}
}

void minus_one(int a[])
{
	int i;

	--a[0];
	for(i = 0; i < MAXN - 1; ++i){
		if(a[i] < 0){
			a[i] += 10;
			--a[i + 1];
		}else{
			break;
		}
	}
	if(a[MAXN - 1] < 0){
		a[MAXN - 1] += 10;
	}
}

int main()
{
	int i, j, r;

	while(scanf("%s", s) == 1 && strcmp(s, "*")){
		if(s[0] >= '0' && s[0] <= '9'){
			if(strcmp(s, "1") == 0){
				printf("%-22s1\n", "a");
				continue;
			}
			//number to word
			memset(a, 0, MAXN * sizeof(int));
			len = strlen(s);
			for(i = 0; i < len; ++i){
				a[i] = s[len - 1 - i] - '0';
			}

			memcpy(a0, a, MAXN * sizeof(int));
			len = 0;
			while(true){
				i = MAXN - 1;
				while(i >= 0 && a[i] == 0){
					--i;
				}
				if(i < 0){
					break;
				}

				for(i = MAXN - 1; i > 0; --i){
					a[i - 1] += a[i] % 26 * 10;
					a[i] = a[i] / 26;
				}
				r = a[0] % 26;
				a[0] = a[0] / 26;
				if(r > 0){
					s[len++] = 'a' + r - 1;
				}else{
					s[len++] = 'z';
					minus_one(a);
				}
			}
			memcpy(a, a0, MAXN * sizeof(int));
			s[len] = 0;

			reverse(s);
			printf("%-22s", s);
			i = MAXN - 1;
			while(i >= 0 && a[i] == 0){
				--i;
			}
			while(i >= 0){
				printf("%d", a[i]);
				if(i > 0 && i % 3 == 0){
					printf(",");
				}
				--i;
			}
			printf("\n");
		}else{
			//word to number
			memset(a, 0, MAXN * sizeof(int));
			for(i = 0; s[i]; ++i){
				for(j = 0; j < MAXN; ++j){
					a[j] *= 26;
				}
				a[0] += s[i] - 'a' + 1;

				for(j = 0; j < MAXN - 1; ++j){
					a[j + 1] += a[j] / 10;
					a[j] %= 10;
				}
				a[j] %= 10;
			}

			printf("%-22s", s);
			i = MAXN - 1;
			while(i >= 0 && a[i] == 0){
				--i;
			}
			while(i >= 0){
				printf("%d", a[i]);
				if(i > 0 && i % 3 == 0){
					printf(",");
				}
				--i;
			}
			printf("\n");
		}
	}

	return 0;
}