CODEWITHSUNDEEP
algorithm
yeahhhmat
yeahhhmat

Reputation: 41

looking for the name of an pattern algorithm

I've manually written 174 possibilities so far and realized I need a better approach. If anyone can nudge me in the right direction, I'm looking for a name for this pattern?

Heres an example:

1
12
123
1234
12345
123456
1234567
12345678
123456789
2
23
234
2345
23456
...

Upvotes: 0

Views: 59

Answers (1)

Daniel
Daniel

Reputation: 7714

I don't know if there is a name for this pattern but it is a simple pattern and can be easily solved with a mixed iterative/recursive functions:

void f(int n = 1){
    if(n > 9) return;  
    for(int i = n; i < 10; i++){
        for(int j = n; j <= i; j++){
            cout<<j;
        }
        cout<<endl;
    }  
    f(n + 1);
}

or

void f(int n = 1){
    if(n > 9) return;
    int i = 0;
    for(int j = n; j < 10; j++) {
        i = i * 10 + j;
        cout<<i<<endl;
    }
    f(n + 1);
}

or

void f(){
    string s = "123456789";
    for(int i = 0; i < 9; i++){
        for(int sz = 1; sz < 10 - i; sz++){
            cout<<s.substr(i, sz)<<endl;
        }
    }
}

or

void f(int n = 0){
    for(int sz = 1; sz < 10 - n; sz++) printf("%.*s\n", sz, "123456789" + n);
    if(n < 10) f(n + 1);
}

Then just call f().

Upvotes: 1

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