What's the complexity (bigO) of this algorithm?

This algorithm look开发者_Go百科s through a string and tries to find another string. The logic is simple, I guess. Though, I need help finding it's complexity.

int find(string mString, string lookUp)
{
    int i, z, j, m = mString.size(), n = lookUp.size(), broken = 0, st = 0;
    for(j = 0, i = 0; i < m; i++)
    {
        if(mString[i] == lookUp[j])
        {
            if(broken)
            {
                //go back and see if we're on the good path
                broken = 0;
                for(z = 0; z < j; z++)
                {
                    if(broken) break;
                    if(mString[i-z] == lookUp[j-z])
                        broken = 0;
                    else
                        broken = 1;
                }
                if(!broken) st = i - j + 1;
            }
            if(j + 1 != n)
                j++;
        }
        else
            broken = 1;
    }
    return st;
}

Can somebody please help me?

Thank you.

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When dealing with big-O and loops, I ask myself the question:

How many times, at most, can each loop run?

In your example,

1. The outer loop will run, at most, `m` times.
2. The inner loop will run, at most, `n` times.
3. For each iteration of the outer loop, the inner loop will run, at most, `n` times

Does this help clarify your thinking?

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O(n^2) is the final complexity of this algorithm.