diff options
Diffstat (limited to 'valid_square.c')
-rw-r--r-- | valid_square.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/valid_square.c b/valid_square.c new file mode 100644 index 0000000..8d1bd06 --- /dev/null +++ b/valid_square.c @@ -0,0 +1,46 @@ +// 593. Valid Square +#include "leetcode.h" + +/* + * given the coordinates of four points in a 2d space 'p1 .. p4', return true if + * the four points oncstruct a square. the coordinate of a point 'p_i' is + * represented as '[x_i, y_i]'. the input is not given in any order. a valid + * square has four equal sides with positive length and four equal angles + * (90-degree angles) + */ + +int dist(int x, int y) { return x * x + y * y; } + +bool validSquare(int *p1, int p1Size, int *p2, int p2Size, int *p3, int p3Size, + int *p4, int p4Size) { + int *p[4] = {p1, p2, p3, p4}, e[2] = {0}; + for (int i = 0; i < 4; i++) { + for (int j = i + 1; j < 4; j++) { + int n = dist(p[i][0] - p[j][0], p[i][1] - p[j][1]); + if (!n) + return false; + if (n == e[0] || (!e[0] && n != e[1])) + e[0] = n; + else if (n == e[1] || (!e[1] && n != e[0])) + e[1] = n; + else + return false; + } + } + return true; +} + +int main() { + int p11[] = {0, 0}, p21[] = {1, 1}, p31[] = {1, 0}, p41[] = {0, 1}; + int p12[] = {0, 0}, p22[] = {1, 1}, p32[] = {1, 0}, p42[] = {0, 12}; + int p13[] = {1, 0}, p23[] = {-1, 0}, p33[] = {0, 1}, p43[] = {0, -1}; + printf("%d\n", + validSquare(p11, ARRAY_SIZE(p11), p21, ARRAY_SIZE(p21), p31, + ARRAY_SIZE(p31), p41, ARRAY_SIZE(p41))); // expect: 1 + printf("%d\n", + validSquare(p12, ARRAY_SIZE(p12), p22, ARRAY_SIZE(p22), p32, + ARRAY_SIZE(p32), p42, ARRAY_SIZE(p42))); // expect: 0 + printf("%d\n", + validSquare(p13, ARRAY_SIZE(p13), p23, ARRAY_SIZE(p23), p33, + ARRAY_SIZE(p33), p43, ARRAY_SIZE(p43))); // expect: 1 +} |