NOIP 1999 邮票面值设计 解题报告

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#define MAX 100001
int str[MAX];
int tmp[MAX];
int len;
int k;

int huiwen(void)
{
int i = 0, j = len - 1;
while(i < j){
if(str[MAX - 1 - i] != str[MAX - 1 - j]){
return 0;
}
i++, j--;
}
return 1;
}

void deal(void)
{
int i;
int j = 0;
memcpy(tmp, str, sizeof(str));
for(i = 0; i < len; i++){
str[MAX - i - 1] = str[MAX - i - 1] + tmp[MAX - len + i] + j;
j = str[MAX - i - 1] / k;
str[MAX - i - 1] %= k;
}
if(j){
str[MAX - i - 1] = j;
len++;
}
}

void getnum(void)
{
char c;
if(scanf("%c", &c) != 1){
return;
}
if(isspace(c)){
return;
}
getnum();
str[MAX - 1 - len] = (int)c;
if(isdigit(c)){
str[MAX - 1 - len] -= '0';
}else if(isalpha(c)){
str[MAX - 1 - len] = toupper(str[MAX - 1 - len]);
str[MAX - 1 - len] -= 'A';
str[MAX - 1 - len] += 10;
}
len++;
}

int main(int argc, char **argv)
{
int i;
scanf("%d\n", &k);
getnum();
for(i = 0; !huiwen() && i <= 30; i++){
deal();
}
if(i == 31){
printf("Impossible\n");
}else{
printf("%d\n", i);
}
return 0;
}