【codechef】Nikhil and Commands（字符串删减，分类）
Nikhil learnt two new commands pwd and cd on the first day of Operating Systems lab.
pwd - command displays the current working directory and,
cd - changes the location of working directory.
If the cd parameter contains ".."(without quotes), that means to step one directory back.
The absolute path of directory is separated by slashes "/"(without quotes).
The default root directory is "/".
Your task is to print the current working directory.
Input
Input description.
- The first line of input contains T, denoting the number of test cases.
- The second line of input contains N, denoting the number of commands.
- Then N lines follow, each containing either a cd command or pwd command.
Output
Output description.
- For each pwd command, output the absolute path of current directory.
Constraints
Should contain all the constraints on the input data that you may have. Format it like:
- 1 ≤ T ≤ 100
- 1 ≤ N ≤ 100
- Maximum length of cd parameter ≤ 200
Example
Input: 1 9 pwd cd /home/csed pwd cd /lab/root/../dir pwd cd /home pwd cd lab pwd Output: / /home/csed/ /lab/dir/ /home/ /home/lab/
点击打开链接
碰到pwd就输出当前路径。出现/..就删它和前面的一个，如果开头没有‘/’则与上面的连接，否则重新开始记录。
功能：函数返回字符串str1中紧接“标记”的部分的指针, 字符串str2是作为标记的分隔符。如果分隔标记没有找到，函数返回NULL。为了将字符串转换成标记，第一次调用str1 指向作为标记的分隔符。之后所以的调用str1 都应为NULL。
例如:
char str[] = "now # is the time for all # good men to come to the # aid of their country";
char delims[] = "#";
char *result = NULL;
result = strtok( str, delims );
while( result != NULL ) {
printf( "result is \"%s\"\n", result );
result = strtok( NULL, delims );
}
以上代码的运行结果是：
result is "now "
result is " is the time for all "
result is " good men to come to the "
result is " aid of their country"
#include<bits/stdc++.h>
using namespace std;
int main(){
int tc; cin>>tc;
while(tc--) {
int cs;
char s[500];
vector<string> u;
scanf("%d",&cs);
while(cs--){
scanf("%s",s);
if(s==string("pwd")){
for(auto& x:u) printf("/%s",x.c_str()); //琢磨一下
puts("/");
}else{
scanf("%s",s);
if(*s=='/') u.clear();
for(char* i=strtok(s,"/");i;i=strtok(0,"/")){ //strtok的用法
if(i==string("..") && u.size()) u.pop_back();
<span style="font-size: 12.380952835083px; font-family: Arial, Helvetica, sans-serif;">if(i==string("..")) </span>u.push_back(i);
}
}
}
}
}
#include <bits/stdc++.h>
using namespace std;
int main(){
int t;
cin>>t;
while(t--){
int n;
cin>>n;
string x;
getchar();
int q=0;
string s="/";
while(n--){
getline(cin,x);
if(x=="pwd"){
cout<<s<<endl;
}
else{
x.erase(0,3);
if(x[0]=='/') //分类
s=x;
else
s+=x;
int p;
for(int i=0;i<s.size();++i){
if(s[i]=='/'&&i+1<s.size()&&s[i+1]!='.')
p=i;
if(i>0&&s[i]=='.'&&s[i-1]=='.'){
s=s.substr(0,p)+s.substr(i+1,s.size()-i-1);
i=-1;
}
}
s+='/';
}
}
}
return 0;
}
#include<bits/stdc++.h>
#define fup(i,n) for(i=1;i<=n;i++)
using namespace std;
int main(){
int t;cin>>t;
while(t--){
int c,pos,i;
cin>>c;
string s = "/",com;
fup(i,c) {
cin>>com;
if(com == "pwd") {
if(s=="/") cout<<"/\n";
else cout<<s<<"/"<<endl;
}
else if( com == "cd") {
cin>>com;
if(com[0] != '/') {
if(s=="/") s+=com;
else s += "/" + com;
}
else s = com;
while( true)
{
int k=s.find(".");
if(k==-1)
break;
//for(int j=0;j<=)
string s1=s.substr(0,k-1);
string s2=s.substr(k+2,s.size()-k-2); //删除中间一段只要找出两边的子串，再拼接起来就行了
k=s1.rfind("/");
s1=s1.substr(0,k);
s=s1+s2;
}
}
}
}
}