UVA10115

Text-processing tools like awk and sed allow you to automatically perform a sequence of editing operations
based on a script. For this problem we consider the specific case in which we want to perform
a series of string replacements, within a single line of text, based on a fixed set of rules. Each rule
specifies the string to find, and the string to replace it with, as shown below.
Rule Find Replace-by
1. ban bab
2. baba be
3. ana any
4. ba b hind the g
To perform the edits for a given line of text, start with the first rule. Replace the first occurrence
of the f ind string within the text by the replace − by string, then try to perform the same replacement
again on the new text. Continue until the f ind string no longer occurs within the text, and then move
on to the next rule. Continue until all the rules have been considered. Note that (1) when searching
for a f ind string, you always start searching at the beginning of the text, (2) once you have finished
using a rule (because the f ind string no longer occurs) you never use that rule again, and (3) case is
significant.
For example, suppose we start with the line
banana boat
and apply these rules. The sequence of transformations is shown below, where occurrences of a f ind
string are underlined and replacements are boldfaced. Note that rule 1 was used twice, then rule 2 was
used once, then rule 3 was used zero times, and then rule 4 was used once.
Before After
banana boat babana boat
babana boat bababa boat
bababa boat beba boat
beba boat behind the goat
Input
The input contains one or more test cases, followed by a line containing only 0 (zero) that signals the
end of the file. Each test case begins with a line containing the number of rules, which will be between
1 and 10. Each rule is specified by a pair of lines, where the first line is the f ind string and the second
line is the replace − by string. Following all the rules is a line containing the text to edit.
Output
For each test case, output a line containing the final edited text.
Note: Both f ind and replace − by strings will be at most 80 characters long. f ind strings will contain
at least one character, but replace − by strings may be empty (indicated in the input file by an empty
line). During the edit process the text may grow as large as 255 characters, but the final output text
will be less than 80 characters long.
The first test case in the sample input below corresponds to the example shown above.
Sample Input
4
ban
bab
baba
be
ana
any
ba b
hind the g
banana boat
1
t
sh
toe or top
0
Sample Output
behind the goat
shoe or shop

这道题的题意是给一些需要替换的字符串以及替换字符串，要在每一组的测试样例的字符串中找出需要替换的字符串，并且用替换字符串把他们替换。由于这道题的rule是有顺序的， 而map会将key自动排序，使rule变乱，所以不能简单的用map做。所以我用了一个struct存储了替换前和替换后的字符串。主要方法就是利用cstring库中的strstr函数来找是否还有需要替换的字符串，如果有则替换。我的替换方法是先复制需替换字符串前面的字符到s3中，再将替换后字符串用strcat连入s3，再用复制函数strcpy将剩下的字符由s复制到s3。一直重复这个替换步骤，直至最后一个rule替换完毕。我觉得我的代码写得不是很好，但也不失为一种方法。

#include <iostream>#include <cstdio>#include <string>#include <map>#include <cstring>using namespace std;const int maxn = 255 + 5;typedef struct replace2{    char s1[maxn], s2[maxn];}REP;void repl(REP a, char *s){    char *p, s3[maxn];    p = strstr (s, a.s1);    if (p == NULL) return;    int po = p - s;    //cout << po << endl;    int l = strlen (a.s1);    memset (s3, '\0', sizeof(s3));    strncpy (s3, s, po);    //puts (s3);    strcat (s3, a.s2);    strcat (s3, p + l);    strcpy (s, s3);    repl (a, s);}int main(){    #ifndef ONLINE_JUDGE    freopen ("in.txt", "r" ,stdin);    #endif // ONLINE_JUDGE    int n;    REP rep[15];    char s[maxn];    while (cin >> n) {        if (n == 0) break;        getchar ();        memset (s, '\0', sizeof(s));        for (int i = 0; i < n; i++) {            gets (rep[i].s1);            gets (rep[i].s2);            //puts (rep[i].s1);            //puts (rep[i].s1);        }        //printf("gyjhbhjb\n");        gets (s);        //cout << s;        for (int i = 0; i < n; i++) {            repl (rep[i], s);        }        puts (s);    }    return 0;}