Reverse conditions in walk function logic

lrvideckis · web-flow · commit 5743f65eb056 · 2026-02-07T17:12:53.000-07:00
diff --git a/library/data_structures_[l,r]/seg_tree_uncommon/walk.hpp b/library/data_structures_[l,r]/seg_tree_uncommon/walk.hpp
@@ -1,8 +1,8 @@
 int walk(int l, int r, const auto& f) {
   while (l <= r) {
     int u = l + n, x = __lg(min(u & -u, r - l + 1));
-    if (f(s[u >> x])) r = l + (1 << x) - 2;
-    else l += 1 << x;
+    if (f(s[u >> x])) l += 1 << x;
+    else r = l + (1 << x) - 2;
   }
   return l;
 }

Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`	`1`	`int walk(int l, int r, const auto& f) {`
`2`	`2`	`while (l <= r) {`
`3`	`3`	`int u = l + n, x = __lg(min(u & -u, r - l + 1));`
`4`		`- if (f(s[u >> x])) r = l + (1 << x) - 2;`
`5`		`- else l += 1 << x;`
	`4`	`+ if (f(s[u >> x])) l += 1 << x;`
	`5`	`+ else r = l + (1 << x) - 2;`
`6`	`6`	`}`
`7`	`7`	`return l;`
`8`	`8`	`}`