diff options
Diffstat (limited to 'num_equivalent_domino_pair.c')
-rw-r--r-- | num_equivalent_domino_pair.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/num_equivalent_domino_pair.c b/num_equivalent_domino_pair.c new file mode 100644 index 0000000..eb9e3d6 --- /dev/null +++ b/num_equivalent_domino_pair.c @@ -0,0 +1,35 @@ +// 1128. Number of Equivalent Domino Pairs +#include "leetcode.h" + +/* + * given a list of 'dominoes', 'dominoes[i] = [a, b]' is equivalent to + * 'dominoes[j] = [c, d]' if and only if either 'a == c' and 'b == d' or 'a == + * d' and 'b == c'. return the number of pairs '(i, j)' for which '0 <= i < j < + * dominoes.length' and 'dominoes[i]' is equivalent to 'dominoes[j]'. + */ + +int numEquivDominoPairs(int **dominoes, int dominoesSize, + int *dominoesColSize) { + int map[100] = {0}, cnt = 0; + for (int i = 0; i < dominoesSize; ++i) { + int u = dominoes[i][0], v = dominoes[i][1]; + int num = u > v ? v * 10 + u : u * 10 + v; + cnt += map[num]; + map[num]++; + } + return cnt; +} + +int main() { + int d1i[4][2] = {{1, 2}, {2, 1}, {3, 4}, {5, 6}}; + int d2i[5][2] = {{1, 2}, {1, 2}, {1, 1}, {1, 2}, {2, 2}}; + struct two_d_arr d1, d2; + two_d_arr_init(&d1, ARRAY_SIZE(d1i), ARRAY_SIZE(d1i[0]), d1i); + two_d_arr_init(&d2, ARRAY_SIZE(d2i), ARRAY_SIZE(d2i[0]), d2i); + printf("%d\n", + numEquivDominoPairs(d1.arr, d1.row_size, d1.col_size)); // expect: 1 + printf("%d\n", + numEquivDominoPairs(d2.arr, d2.row_size, d2.col_size)); // expect: 3 + two_d_arr_free(&d1); + two_d_arr_free(&d2); +} |