#include <stdio.h>
#include <math.h>
int g_maxValue = 6;
// ====================SolutionI====================
void Probability(int number, int* pProbabilities);
void Probability(int original, int current, int sum, int* pProbabilities);
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(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, sum+i, pProbabilities);
}
//=========================SolutionII============================
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;
}
//当前辅助数组
int aidFlag = 0;
for(int i=1; i<=g_maxValue; ++i)
pProbabilities[aidFlag][i] = 1;
for(int curr=2; curr<=number; ++curr) { //curr:当前骰子颗数
for(int i=curr; i<=g_maxValue*curr; ++i) {
pProbabilities[1-aidFlag][i] = 0;
for(int j=1; j<=g_maxValue && (i-j>=1); ++j)
pProbabilities[1-aidFlag][i] += pProbabilities[aidFlag][i-j];
}
aidFlag = 1 - aidFlag;
}
double total = pow((double)g_maxValue, number);
for(int i=number; i<=g_maxValue*number; ++i) {
double ratio = (double)pProbabilities[aidFlag][i] / total;
printf("%d: %e\n", i, ratio);
}
delete[] pProbabilities[0];
delete[] pProbabilities[1];
}
// ====================TEST====================
void Test(int n)
{
printf("Test for %d begins:\n", n);
// printf("Test for solution1\n");
// PrintProbability_Solution1(n);
printf("Test for solution2\n");
PrintProbability_Solution2(n);
printf("\n");
}
int main(int argc, char* argv[])
{
Test(1);
Test(2);
Test(3);
Test(4);
Test(11);
Test(0);
return 0;
}