我试了一下你的程序
把qsort去掉就AC了

> #include <stdio.h>
> #include <string.h>
> #include <stdlib.h>
> 
> #define N 10001
> #define M 27
> 
> char s[N][M],word[M];
> int id[N];
> 
> int cmp(const void *x,const void *y) {
> int a=*(int*) x,b=*(int*) y;
> 	return strcmp(s[a],s[b]);
> }
> 
> int replace(char *s,char *w) {
> int lens=strlen(s),lenw=strlen(w),i,p;
> 	if (lens==lenw) {
> 		p=0;
> 		for (i=0;i<lens;++i)
> 			if (s[i]!=w[i]) {
> 				if (p) return 0;
> 				p=1;
> 			}
> 		return 1;
> 	}
> 	if (lens+1==lenw) {
> 		i=0;
> 		while ((i<lens) && (s[i]==w[i])) ++i;
> 		for (++i;i<lenw;++i)
> 			if (s[i-1]!=w[i]) return 0;
> 		return 1;
> 	}
> 	if (lens==lenw+1) {
> 		i=0;
> 		while ((i<lenw) && (s[i]==w[i])) ++i;
> 		for (++i;i<lens;++i)
> 			if (s[i]!=w[i-1]) return 0;
> 		return 1;
> 	}
> 	return 0;
> }
> 
> main() {
> int z,n,i;
> 	
> 	for (z=1;z>0;--z) {
> 		for (n=0;;++n) {
> 			scanf("%s",s[n]);
> 			if (s[n][0]=='#') break;
> 			id[n]=n;
> 		}
> 		qsort(id,n,sizeof(int),cmp);
> 		while (1) {
> 			scanf("%s",word);
> 			if (word[0]=='#') break;
> 			for (i=0;i<n;++i)
> 				if (!strcmp(s[i],word)) break;
> 			if (i<n) {
> 				printf("%s is correct\n",word);
> 				continue;
> 			}
> 			printf("%s:",word);
> 			for (i=0;i<n;++i) 
> 				if (replace(s[id[i]],word)) printf(" %s",s[id[i]]);
> 			printf("\n");
> 		}
> 		if (z>1) printf("\n");
> 	}
> }
> 			
>