剑指offer——面试题43：n个骰子的点数

void PrintProbability_Solution1(int number)
{
if(number < 1)
return;

int maxSum = number * g_maxValue;
int* pProbabilities = new int[maxSum - number + 1];
for(int i = number; i <= maxSum; ++i)
pProbabilities[i - number] = 0;

Probability(number, pProbabilities);

int total = pow((double)g_maxValue, number);
for(int i = number; i <= maxSum; ++i)
{
double ratio = (double)pProbabilities[i - number] / total;
printf("%d: %e\n", i, ratio);
}

delete[] pProbabilities;
}

void Probability(int number, int* pProbabilities)
{
for(int i = 1; i <= g_maxValue; ++i)
Probability(number, number, i, pProbabilities);
}

void Probability(int original, int current, int sum,
int* pProbabilities)
{
if(current == 1)
{
pProbabilities[sum - original]++;
}
else
{
for(int i = 1; i <= g_maxValue; ++i)
{
Probability(original, current - 1, i + sum, pProbabilities);
}
}
}





void PrintProbability_Solution2(int number)
{
if(number < 1)
return;

int* pProbabilities[2];
pProbabilities[0] = new int[g_maxValue * number + 1];
pProbabilities[1] = new int[g_maxValue * number + 1];
for(int i = 0; i < g_maxValue * number + 1; ++i)
{
pProbabilities[0][i] = 0;
pProbabilities[1][i] = 0;
}

int flag = 0;
for (int i = 1; i <= g_maxValue; ++i)
pProbabilities[flag][i] = 1;

for (int k = 2; k <= number; ++k)
{
for(int i = 0; i < k; ++i)
pProbabilities[1 - flag][i] = 0;

for (int i = k; i <= g_maxValue * k; ++i)
{
pProbabilities[1 - flag][i] = 0;
for(int j = 1; j <= i && j <= g_maxValue; ++j)
pProbabilities[1 - flag][i] += pProbabilities[flag][i - j];
}

flag = 1 - flag;
}

double total = pow((double)g_maxValue, number);
for(int i = number; i <= g_maxValue * number; ++i)
{
double ratio = (double)pProbabilities[flag][i] / total;
printf("%d: %e\n", i, ratio);
}

delete[] pProbabilities[0];
delete[] pProbabilities[1];
}