pe205.cpp

// pe205.cpp: определяет точку входа для консольного приложения.
//

#include "stdafx.h"

int* add_one(int* brs, int max, int count) {
	for (int i = count-1; i >= 0; i--) {
		if (brs[i] < max) {
			brs[i]++;
			for (int j = i+1; j < count; j++) {
				brs[j] = 1;
			}
			return brs;
		}
	}
	return brs;
}

int sum(int* brs, int count) {
	int res = 0;
	for (int i = 0; i < count; i++) {
		res += brs[i];
	}
	return res;
}

unsigned long dice_sums(int** res, int max, int count)
{
	unsigned long length = pow((double)max, count);
	int* result = new int[length];
	int* last_br = new int[count];
	for (int i = 0; i < count; i++) {
		last_br[i] = 1;
	}
	printf("Computing %u sums... ", length);
	for (int i = 0; i < length; i++) {
		result[i] = sum(last_br, count);
		add_one(last_br, max, count);
	}
	printf("Ready.\n");
	*res = result;
	delete last_br;
	return length;
}

int _tmain(int argc, _TCHAR* argv[])
{
	int* first = NULL;
	int* second = NULL;
	unsigned long long fc = dice_sums(&first, 4, 9);
	unsigned long long sc = dice_sums(&second, 6, 6);
	unsigned long long total = 0;
	unsigned long long fwon = 0;
	
	int* cache = new int[40];
	memset(cache, 0, sizeof(int) * 40);

	printf("Computing %I64d * %I64d = %I64d games...\n", fc, sc, fc * sc);
	getchar();
	for (int i = 0; i < fc; i++) {
		if (cache[first[i]] == 0)
			for (int j = 0; j < sc; j++) {
				if (first[i] > second[j])
					cache[first[i]]++;
			}
		fwon += cache[first[i]];
		total += sc;
		if (i % 1000 == 0) printf(" i = %i\n", i);
	}

	printf("\nTotal games: %I64d. First won %I64d times. Probability = %0.7f", total, fwon, fwon / total);

	getchar();
	return 0;
}