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// 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);
}
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