UVA 213 Message Decoding——思路题

紫书例题，具体参考紫书P83；

顺便补充一点小知识：代码中的1<<len表示2^len

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

int readchar()
{
    while(1){
        int ch = getchar();
        if(ch != '\n' && ch != '\r') return ch;//一直读到非换行符为止
    }
}

int readint(int c)
{
    int v = 0;
    while(c--) v = v * 2 + readchar() - '0';
    return v;
}

int code[8][1<<8];

int readcodes()
{
    int i,len;
    memset(code,0,sizeof(code));
    code[1][0] = readchar();//直接跳到下一行开始读取,若输入已结束，会读到EOF
    for(len = 2; len <=7; len++){
        for(i = 0; i < (1<<len)-1; i++){
            int ch = getchar();
            if(ch == EOF) return 0;
            if(ch == '\n' || ch == '\r') return 1;
            code[len][i] = ch;
        }
    }
    return 1;
}

int main()
{
    while( readcodes() ){
        while(1){
            int len = readint(3);
            if(len == 0) break;
            while(1){
                int v = readint(len);
                if(v == (1<<len) - 1) break;
                putchar(code[len][v]);
            }
        }
        putchar('\n');
    }
    return 0;
}