Euler18 Faster c++

#include <stdio.h>
#include <ctime>
#include <iostream>

int grid[15][15] = {
        {75},
        {95, 64},
        {17, 47, 82},
        {18, 35, 87, 10},
        {20, 4, 82, 47, 65},
        {19, 1, 23, 75, 3, 34},
        {88, 2, 77, 73, 7, 63, 67},
        {99, 65, 4, 28, 6, 16, 70, 92},
        {41, 41, 26, 56, 83, 40, 80, 70, 33},
        {41, 48, 72, 33, 47, 32, 37, 16, 94, 29},
        {53, 71, 44, 65, 25, 43, 91, 52, 97, 51, 14},
        {70, 11, 33, 28, 77, 73, 17, 78, 39, 68, 17, 57},
        {91, 71, 52, 38, 17, 14, 91, 43, 58, 50, 27, 29, 48},
        {63, 66, 4, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31},
        {4, 62, 98, 27, 23, 9, 70, 98, 73, 93, 38, 53, 60, 4, 23}
};

int main() {

    int max = 0;
    int tmp;

    std::clock_t start;
    start = std::clock();
    for (int a = 0; a < 1; a++) {
        for (int b = 0; b < 2; b++) {
            for (int c = 0; c < 3; c++) {
                if (c != b + 1 && c != b)
                    continue;
                for (int d = 0; d < 4; d++) {
                    if (d != c + 1 && d != c)
                        continue;
                    for (int e = 0; e < 5; e++) {
                        if (e != d + 1 && e != d)
                            continue;
                        for (int f = 0; f < 6; f++) {
                            if (f != e + 1 && f != e)
                                continue;
                            for (int g = 0; g < 7; g++) {
                                if (g != f + 1 && g != f)
                                    continue;
                                for (int h = 0; h < 8; h++) {
                                    if (h != g + 1 && h != g)
                                        continue;
                                    for (int i = 0; i < 9; i++) {
                                        if (i != h + 1 && i != h)
                                            continue;
                                        for (int j = 0; j < 10; j++) {
                                            if (j != i + 1 && j != i)
                                                continue;
                                            for (int k = 0; k < 11; k++) {
                                                if (k != j + 1 && k != j)
                                                    continue;
                                                for (int l = 0; l < 12; l++) {
                                                    if (l != k + 1 && l != k)
                                                        continue;
                                                    for (int m = 0; m < 13; m++) {
                                                        if (m != l + 1 && m != l)
                                                            continue;
                                                        for (int n = 0; n < 14; n++) {
                                                            if (n != m + 1 && n != m)
                                                                continue;
                                                            for (int o = 0; o < 15; o++) {
                                                                if (o != n + 1 && o != n)
                                                                    continue;
                                                                tmp = grid[0][a] + \
                                                                    grid[1][b] + \
                                                                    grid[2][c] + \
                                                                    grid[3][d] + \
                                                                    grid[4][e] + \
                                                                    grid[5][f] + \
                                                                    grid[6][g] + \
                                                                    grid[7][h] + \
                                                                    grid[8][i] + \
                                                                    grid[9][j] + \
                                                                    grid[10][k] + \
                                                                    grid[11][l] + \
                                                                    grid[12][m] + \
                                                                    grid[13][n] + \
                                                                    grid[14][o];
                                                                if (tmp > max) {
                                                                    max = tmp;
                                                                    printf("%d (%.3f seconds elapsed)\r\n", max, (std::clock() - start) / (double)CLOCKS_PER_SEC);

                                                                }
                                                            }
                                                        }
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    printf("MAX: %d\r\n", max);

    printf("Finished In:\r\n");
    printf("              %.3f Seconds.\r\n", ((std::clock() - start) / (double)CLOCKS_PER_SEC));
    printf("              %.2f Minutes.\r\n", ((std::clock() - start) / (double)CLOCKS_PER_SEC) / 60);
    printf("              %.3f Hours.\r\n", ((std::clock() - start) / (double)CLOCKS_PER_SEC) / 60 / 60);
    getchar();
    return 0;
}
/*
OUTPUT:
794 (0.000 seconds elapsed)
852 (0.000 seconds elapsed)
855 (0.000 seconds elapsed)
891 (0.000 seconds elapsed)
907 (0.001 seconds elapsed)
916 (0.001 seconds elapsed)
934 (0.001 seconds elapsed)
940 (0.001 seconds elapsed)
955 (0.001 seconds elapsed)
964 (0.001 seconds elapsed)
982 (0.001 seconds elapsed)
988 (0.001 seconds elapsed)
*** (0.001 seconds elapsed)
**** (0.001 seconds elapsed)
**** (0.001 seconds elapsed)
**** (0.001 seconds elapsed)
**** (0.001 seconds elapsed)
**** (0.001 seconds elapsed)
**** (0.001 seconds elapsed)
**** (0.001 seconds elapsed)
**** (0.002 seconds elapsed)
MAX: ****
Finished In:
              0.002 Seconds.
              0.00 Minutes.
              0.000 Hours.


*/