//第一题  #include <stdio.h> #include<iostream> #include<ctime> #include<cstdlib> #include<cmath> using namespace std; int main() {     string s;     int ans(0),x;     cin>>s;     for(int i=0;i<s.length();i++)     {         if(isalpha(s[i])==0)         {            x=s[i]-'0';            while(isalpha(s[++i])==0 && i<s.length())                 x=x*10+s[i]-'0';            if(x>ans)ans=x;         }     }     cout<<ans;   return 0; }  //第二题  #include<iostream> #include<string> #include<algorithm> using namespace std; int z[10]; int main() {     int n;     cin>>n;     for(int i=0;i<n;i++){         cin>>z[i];     }     for(int i=0;i<n;){         if(z[i+1]-1==z[i]){             int cc=i;             int num=0;             while(z[i+1]-1==z[i]){                 num++;                 i++;             }             if(num>=2){                 if(cc!=0){                     cout<<',';                              }                 cout<<z[cc]<<'-'<<z[i];                 i++;                 }             else {                 i=cc;                 if(cc!=0){                     cout<<',';                 }                 cout<<z[i];                 i++;                              }                      }         else {             if(i!=0){                     cout<<',';                 }                 cout<<z[i];                 i++;         }     }     return 0; }  //第三题  #include <stdio.h> #include<iostream> #include<ctime> #include<cstdlib> #include<cmath> #include<algorithm> using namespace std; int main() {     int n;     int a[110];     cin>>n;     for(int i=0;i<n;i++)         cin>>a[i];     for(int i=0;i<n;i++)             cout<<a[i];     cout<<endl;     while(next_permutation(a,a+n))     {         for(int i=0;i<n;i++)             cout<<a[i];         cout<<endl;     }   return 0; }