How can i get array index to satisfy my requirement fastly?
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Hi ,i have a questions ,and i don't know how to handle it. I have a double array named array1=new double[100], and each element is function result, like array1[0]=fun(0),array2[1]=fun(1)... each element is positive or negative, and generally speaking, a[0] to a[n] is positive, and a[n+1] to end is negative, so how can i get n ? i need efficient algorithm, like divide-and-conquer method for example... and case 2: if near the end i get wrong result, for example, a[90] is +,how can i get the first negative index n ?
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Hi ,i have a questions ,and i don't know how to handle it. I have a double array named array1=new double[100], and each element is function result, like array1[0]=fun(0),array2[1]=fun(1)... each element is positive or negative, and generally speaking, a[0] to a[n] is positive, and a[n+1] to end is negative, so how can i get n ? i need efficient algorithm, like divide-and-conquer method for example... and case 2: if near the end i get wrong result, for example, a[90] is +,how can i get the first negative index n ?
In case one, a simple Binary search algorithm - Wikipedia, the free encyclopedia[^] should do it, assumign there is no "bad" data. When you data goes bad, that's different, and it becomes necessary to actually search the whole array - if there is one bad value, then it's likely there are more. But the alternative to both is to to it all while you fill the array - since that is already a time consuming process (compared to a search of the results) adding a little extra checking to find the first negative as you fill the values is trivial, and allows you to cope with the second case as well.
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