Data commit

Task/Hilbert-curve/C/hilbert-curve.c

@@ -0,0 +1,71 @@
+#include <stdio.h>
+
+#define N 32
+#define K 3
+#define MAX N * K
+
+typedef struct { int x; int y; } point;
+
+void rot(int n, point *p, int rx, int ry) {
+    int t;
+    if (!ry) {
+        if (rx == 1) {
+            p->x = n - 1 - p->x;
+            p->y = n - 1 - p->y;
+        }
+        t = p->x;
+        p->x = p->y;
+        p->y = t;
+    }
+}
+
+void d2pt(int n, int d, point *p) {
+    int s = 1, t = d, rx, ry;
+    p->x = 0;
+    p->y = 0;
+    while (s < n) {
+        rx = 1 & (t / 2);
+        ry = 1 & (t ^ rx);
+        rot(s, p, rx, ry);
+        p->x += s * rx;
+        p->y += s * ry;
+        t /= 4;
+        s *= 2;
+    }
+}
+
+int main() {
+    int d, x, y, cx, cy, px, py;
+    char pts[MAX][MAX];
+    point curr, prev;
+    for (x = 0; x < MAX; ++x)
+        for (y = 0; y < MAX; ++y) pts[x][y] = ' ';
+    prev.x = prev.y = 0;
+    pts[0][0] = '.';
+    for (d = 1; d < N * N; ++d) {
+        d2pt(N, d, &curr);
+        cx = curr.x * K;
+        cy = curr.y * K;
+        px = prev.x * K;
+        py = prev.y * K;
+        pts[cx][cy] = '.';
+        if (cx == px ) {
+            if (py < cy)
+                for (y = py + 1; y < cy; ++y) pts[cx][y] = '|';
+            else
+                for (y = cy + 1; y < py; ++y) pts[cx][y] = '|';
+        }
+        else {
+            if (px < cx)
+                for (x = px + 1; x < cx; ++x) pts[x][cy] = '_';
+            else
+                for (x = cx + 1; x < px; ++x) pts[x][cy] = '_';
+        }
+        prev = curr;
+    }
+    for (x = 0; x < MAX; ++x) {
+        for (y = 0; y < MAX; ++y) printf("%c", pts[y][x]);
+        printf("\n");
+    }
+    return 0;
+}