From: Attractive Chaos <attractor@live.co.uk>
Date: Thu, 19 Dec 2019 18:35:12 +0000 (-0500)
Subject: RMQ apparently working on a small dataset
X-Git-Url: http://www.kaiwu.me/postgresql/commit/static/gitweb.js?a=commitdiff_plain;h=edea354917220a037ec9e5ea9f9a4b5835cd0d25;p=klib.git

RMQ apparently working on a small dataset
---

diff --git a/krmq.h b/krmq.h
index bbb2164..b2ba944 100644
--- a/krmq.h
+++ b/krmq.h
@@ -107,6 +107,48 @@ int main(void) {
 		return (__type*)p; \
 	}
 
+#define __KRMQ_RMQ(suf, __scope, __type, __head,  __cmp, __lt2) \
+	__scope __type *krmq_rmq_##suf(const __type *root, const __type *lo, const __type *up) { /* CLOSED interval */ \
+		const __type *p = root, *path[2][KRMQ_MAX_DEPTH], *min; \
+		int plen[2] = {0, 0}, pcmp[2][KRMQ_MAX_DEPTH], i, cmp, lca; \
+		if (root == 0) return 0; \
+		while (p) { \
+			cmp = __cmp(lo, p); \
+			path[0][plen[0]] = p, pcmp[0][plen[0]++] = cmp; \
+			if (cmp < 0) p = p->__head.p[0]; \
+			else if (cmp > 0) p = p->__head.p[1]; \
+			else break; \
+		} \
+		p = root; \
+		while (p) { \
+			cmp = __cmp(up, p); \
+			path[1][plen[1]] = p, pcmp[1][plen[1]++] = cmp; \
+			if (cmp < 0) p = p->__head.p[0]; \
+			else if (cmp > 0) p = p->__head.p[1]; \
+			else break; \
+		} \
+		for (i = 0; i < plen[0] && i < plen[1]; ++i) \
+			if (path[0][i] == path[1][i] && pcmp[0][i] <= 0 && pcmp[1][i] >= 0) \
+				break; \
+		if (i == plen[0] || i == plen[1]) return 0; /* no elements in the closed interval */ \
+		lca = i, min = path[0][lca]; \
+		for (i = lca + 1; i < plen[0]; ++i) { \
+			if (pcmp[0][i] <= 0) { \
+				if (__lt2(path[0][i], min)) min = path[0][i]; \
+				if (path[0][i]->__head.p[1] && __lt2(path[0][i]->__head.p[1]->__head.s, min)) \
+					min = path[0][i]->__head.p[1]->__head.s; \
+			} \
+		} \
+		for (i = lca + 1; i < plen[1]; ++i) { \
+			if (pcmp[1][i] >= 0) { \
+				if (__lt2(path[1][i], min)) min = path[1][i]; \
+				if (path[1][i]->__head.p[0] && __lt2(path[1][i]->__head.p[0]->__head.s, min)) \
+					min = path[1][i]->__head.p[0]->__head.s; \
+			} \
+		} \
+		return (__type*)min; \
+	}
+
 #define __KRMQ_ROTATE(suf, __type, __head, __lt2) \
 	/* */ \
 	static inline void krmq_update_min_##suf(__type *p, const __type *q, const __type *r) { \
@@ -257,7 +299,7 @@ int main(void) {
 				r->__head.size = p->__head.size - 1; \
 			} \
 		} \
-		for (i = d - 1; i >= 0; --i) /* not sure why adding condition "path[i]==p" doesn't work */ \
+		for (i = d - 1; i >= 0; --i) /* not sure why adding condition "path[i]->__head.s==p" doesn't work */ \
 			krmq_update_min_##suf(path[i], path[i]->__head.p[0], path[i]->__head.p[1]); \
 		while (--d > 0) { \
 			__type *q = path[d]; \
@@ -361,6 +403,7 @@ int main(void) {
  */
 #define krmq_find(suf, root, x, cnt) krmq_find_##suf(root, x, cnt)
 #define krmq_interval(suf, root, x, lower, upper) krmq_interval_##suf(root, x, lower, upper)
+#define krmq_rmq(suf, root, lo, up) krmq_rmq_##suf(root, lo, up)
 
 /**
  * Delete a node from the tree
@@ -419,6 +462,7 @@ int main(void) {
 
 #define KRMQ_INIT2(suf, __scope, __type, __head, __cmp, __lt2) \
 	__KRMQ_FIND(suf, __scope, __type, __head,  __cmp) \
+	__KRMQ_RMQ(suf, __scope, __type, __head,  __cmp, __lt2) \
 	__KRMQ_ROTATE(suf, __type, __head, __lt2) \
 	__KRMQ_INSERT(suf, __scope, __type, __head, __cmp, __lt2) \
 	__KRMQ_ERASE(suf, __scope, __type, __head, __cmp, __lt2) \
diff --git a/test/krmq_test.c b/test/krmq_test.c
index 32b48ba..8af20ca 100644
--- a/test/krmq_test.c
+++ b/test/krmq_test.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <assert.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
@@ -38,6 +39,27 @@ int check(struct my_node *p, int *hh, int *min)
 	} else return 0;
 }
 
+int check_rmq(const struct my_node *root, int lo, int hi)
+{
+	struct my_node s, t, *p, *q;
+	krmq_itr_t(my) itr;
+	int min = INT_MAX;
+	s.key = lo, t.key = hi;
+	p = krmq_rmq(my, root, &s, &t);
+	krmq_interval(my, root, &s, 0, &q);
+	if (p == 0) return -1;
+	krmq_itr_find(my, root, q, &itr);
+	do {
+		const struct my_node *r = krmq_at(&itr);
+		if (r->key > hi) break;
+		//fprintf(stderr, "%c\t%d\n", r->key, r->val);
+		if (r->val < min) min = r->val;
+	} while (krmq_itr_next(my, &itr));
+	assert((min == INT_MAX && p == 0) || (min < INT_MAX && p));
+	if (min != p->val) fprintf(stderr, "rmq_min %d != %d\n", p->val, min);
+	return min;
+}
+
 int print_tree(const struct my_node *p)
 {
 	int c = 1;
@@ -95,6 +117,7 @@ int main(void)
 		if (p != q) free(p);
 		check(root, &h, &min);
 	}
+
 	shuffle(n, buf);
 	for (i = 0; i < n/2; ++i) {
 		t.key = buf[i];
@@ -105,6 +128,12 @@ int main(void)
 	}
 	check_and_print(root);
 
+	check_rmq(root, '0', '9');
+	check_rmq(root, '!', '~');
+	check_rmq(root, 'A', 'Z');
+	check_rmq(root, 'F', 'G');
+	check_rmq(root, 'a', 'z');
+
 	krmq_itr_first(my, root, &itr);
 	do {
 		const struct my_node *r = krmq_at(&itr);