ZOJ Problem Set - 1042 W's Cipher

cipher.c

#include <stdio.h>
#include <string.h>
#define MAX 80

char code1[MAX+1];
int pos1[MAX+1];
int code1_i, pos1_i ,len1;

char code2[MAX+1];
int pos2[MAX+1];
int code2_i, pos2_i ,len2;

char code3[MAX+1];
int pos3[MAX+1];
int code3_i, pos3_i ,len3;

int k1, k2, k3;

char input[MAX+1];
int i;

int main() {
	scanf("%d %d %d", &k1, &k2, &k3);
	while(k1 != 0 && k2 != 0 && k3 != 0) {
		scanf("%s",input);
		len1 = len2 = len3 = 0;
		for(i = 0; i < strlen(input); ++i) {
			if (input[i] >= 'a' && input[i] <= 'i') {
				code1[len1] = input[i];
				pos1[len1] = i;
				len1++;
			} else if (input[i] >= 'j' && input[i] <= 'r') {
				code2[len2] = input[i];
				pos2[len2] = i;
				len2++;
			} else {
				code3[len3] = input[i];
				pos3[len3] = i;
				len3++;
			}
		}
		pos1_i = pos2_i = pos3_i = code1_i = code2_i = code3_i = 0;
		
		for(i = 0; i < k1; ++i) {
			code1_i--;
			if (code1_i < 0)
				code1_i = len1-1;
		}
		for(i = 0; i < k2; ++i) {
			code2_i--;
			if (code2_i < 0)
				code2_i = len2-1;
		}
		for(i = 0; i < k3; ++i) {
			code3_i--;
			if (code3_i < 0)
				code3_i = len3-1;
		}
		for(i = 0; i < len1; ++i) {
			input[pos1[pos1_i]] = code1[code1_i];
			pos1_i++;
			code1_i++;
			if (code1_i == len1)
				code1_i = 0;
		}
		for(i = 0; i < len2; ++i) {
			input[pos2[pos2_i]] = code2[code2_i];
			pos2_i++;
			code2_i++;
			if (code2_i == len2)
				code2_i = 0;
		}
		for(i = 0; i < len3; ++i) {
			input[pos3[pos3_i]] = code3[code3_i];
			pos3_i++;
			code3_i++;
			if (code3_i == len3)
				code3_i = 0;
		}
		printf("%s\n",input);
		scanf("%d %d %d", &k1, &k2, &k3);
	}
	return 0;
}