diff options
Diffstat (limited to 'min_domino_rotation_eq_row.c')
-rw-r--r-- | min_domino_rotation_eq_row.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/min_domino_rotation_eq_row.c b/min_domino_rotation_eq_row.c new file mode 100644 index 0000000..9a214cb --- /dev/null +++ b/min_domino_rotation_eq_row.c @@ -0,0 +1,40 @@ +// 1007. Minimum Domino Rotations For Equal Row +#include "leetcode.h" + +/* + * in a row of dominoes, 'tops[i]' and 'bottoms[i]' represents the top and + * bottom halves of the i'th domino. we may rotate the i'th domino so that + * 'tops[i]' and 'bottoms[i]' swap values. return the minimum number of + * rotations so that all values in 'tops' are the same, or all values in + * 'bottoms' are the same. if it cannot be done, return -1. + */ + +int minDominoRotations(int *tops, int topsSize, int *bottoms, int bottomsSize) { + int mask = 0x7E, num = -1, a = 0, b = 0; + for (int i = 0; i < topsSize; i++) { + mask &= ((1 << tops[i]) | (1 << bottoms[i])); + if (!mask) + return -1; + } + while (mask) { + num++; + mask >>= 1; + } + for (int i = 0; i < topsSize; i++) { + if (tops[i] == num) + a++; + if (bottoms[i] == num) + b++; + } + int max = a > b ? a : b; + return topsSize - max; +} + +int main() { + int t1[] = {2, 1, 2, 4, 2, 2}, b1[] = {5, 2, 6, 2, 3, 2}; + int t2[] = {3, 5, 1, 2, 3}, b2[] = {3, 6, 3, 3, 4}; + printf("%d\n", minDominoRotations(t1, ARRAY_SIZE(t1), b1, + ARRAY_SIZE(b1))); // expect: 2 + printf("%d\n", minDominoRotations(t2, ARRAY_SIZE(t2), b2, + ARRAY_SIZE(b2))); // expect: -1 +} |