give the order of growth in big-o notation as a function of n.

Please explain your reasoning

int total = 0;

for (int z = r; z > 0; z /= 2)

for (int k = 0; k < z; k++)

total++;

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int total = 0;

for (int j = 1; j < t; i *= 2)

for (int k = 0; k < j; k++)

total++;

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int total = 0;

for ( int j = 1; j < k; j *= 2)

for (int r = 0; r< k; r++)

total++;