套汇问题 Floyd

问题：套汇。

思路：Floyd

代码：

#include <cstdio>
#include <cstdlib>
#include <ctime>

#define N 10

int currencyArbitrage (double rates[][N]);

int main (int argc, char **argv)
{
    double R[N][N];
    srand(time(NULL));
    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            R[i][j] = ((rand() % N) + 1) * 1.0 / N;
        }
    }
    R[1][2] = 1;
    R[2][6] = 0.9;
    R[6][1] = 1.2;

    printf("%d
",currencyArbitrage(R));
    return 0;
}

int currencyArbitrage (double rates[][N])
{
    for (int k = 0; k < N; k++)
        for (int i = 0; i < N; i++)
            for (int j = 0; j < N; j++)
            {
                double tmp = rates[i][k] * rates[k][j];
                rates[i][j] = (tmp > rates[i][j]) ? tmp : rates[i][j];
                if ((i != j) && (rates[i][j] * rates[j][i] > 1))
                {
                    return 1;
                }
            }
    return 0;
}

时间复杂度：O(N^3)