Recursive call-doubt

#1

I know this is silly but can you please explain how does the recursive call happens in the code below.

void solve(int n,int m)
{

if(m==0)
{

    if(n==x)
        cnt++;

    return;
}

solve(n+1,m-1);
solve(n-1,m-1);

}

#2

let’s say n=10, x=9 and m=4

so this will be the recursion tree

                                10                           m=4
                           /           \
                      9                    11                m=3
                 /        \             /       \
                8           10       10            12        m=2
              /    \       /    \    /    \      /      \
           7        9   11     12 9      11  12          13  m=1

first solve(n+1,m-1) is called so n will be incremented till m=0;
once m=0 we will do the increment on cnt if the condition is satisfied and return after that and we return to the function and call solve(n-1,m-1) and so we call solve((n-1)+1, (m-1)-1) and so on

1 Like
#3

understood.
thanks mate! :grin:

#4

that’s good to know in case of any doubt feel free to ask me :slight_smile:
if you got the answer mark your answer as resolved !!

#5

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