From cfde1dabc2667c57468f82410621d586ac2fcad2 Mon Sep 17 00:00:00 2001
From: Bruno Freitas Tissei <bft15@inf.ufpr.br>
Date: Fri, 3 May 2019 16:43:16 -0300
Subject: [PATCH] Fix seg trees and dsu
Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>
---
algorithms/structure/disjoint_set.cpp | 24 +++++++++-------------
algorithms/structure/lazy_segment_tree.cpp | 23 ++++++++++++---------
algorithms/structure/segment_tree.cpp | 23 ++++++++++++---------
3 files changed, 36 insertions(+), 34 deletions(-)
diff --git a/algorithms/structure/disjoint_set.cpp b/algorithms/structure/disjoint_set.cpp
index be2dd24..1635131 100644
--- a/algorithms/structure/disjoint_set.cpp
+++ b/algorithms/structure/disjoint_set.cpp
@@ -8,17 +8,16 @@
struct DisjointSet {
int N;
- vector<int> h, par, size;
+ vector<int> rank, par;
Disjoint(int N) :
- N(N), h(N), par(N), size(N)
+ N(N), rank(N), par(N)
{}
/// Initializes element x.
void make_set(int x) {
par[x] = x;
- h[x] = 0;
- size[x] = 1;
+ rank[x] = 0;
}
/// Returns set index from element x.
@@ -33,16 +32,13 @@ struct DisjointSet {
x = find_set(x);
y = find_set(y);
- if (x == y)
- return;
+ if (x != y) {
+ if (rank[x] > rank[y])
+ swap(x, y);
- if (h[x] > h[y])
- swap(x, y);
-
- par[x] = y;
- size[y] += size[x];
-
- if (h[x] == h[y])
- h[x]++;
+ par[x] = y;
+ if (rank[x] == rank[y])
+ rank[x]++;
+ }
}
};
diff --git a/algorithms/structure/lazy_segment_tree.cpp b/algorithms/structure/lazy_segment_tree.cpp
index aee0052..cd56303 100644
--- a/algorithms/structure/lazy_segment_tree.cpp
+++ b/algorithms/structure/lazy_segment_tree.cpp
@@ -6,11 +6,11 @@
/// query_tree -> O(log n)
/// Complexity (Space): O(n)
+int N;
struct LazySegmentTree {
- int N;
vector<int> tree, lazy;
- LazySegmentTree(int N, const vector<int> &v) : N(N), tree(N*4), lazy(N*4) {
+ LazySegmentTree(const vector<int> &v) : tree(MAX*4), lazy(MAX*4) {
init();
build(v);
}
@@ -34,9 +34,10 @@ struct LazySegmentTree {
return;
}
- build(v, left(node), a, (a + b) / 2);
- build(v, right(node), (a + b) / 2 + 1, b);
- tree[node] = tree[node * 2] + tree[node * 2 + 1];
+ int mid = (a + b) / 2;
+ build(v, left(node), a, mid);
+ build(v, right(node), mid + 1, b);
+ tree[node] = tree[left(node)] + tree[right(node)];
}
/// Propagates value to tree and through lazy tree.
@@ -70,9 +71,10 @@ struct LazySegmentTree {
return;
}
- update(i, j, val, left(node), a, (a + b) / 2);
- update(i, j, val, right(node), (a + b) / 2 + 1, b);
- tree[node] = tree[node * 2] + tree[node * 2 + 1];
+ int mid = (a + b) / 2;
+ update(i, j, val, left(node), a, mid);
+ update(i, j, val, right(node), mid + 1, b);
+ tree[node] = tree[left(node)] + tree[right(node)];
}
/// Returns sum of [i,j].
@@ -87,8 +89,9 @@ struct LazySegmentTree {
if (a >= i && b <= j)
return tree[node];
- int q1 = query(i, j, left(node), a, (a + b) / 2);
- int q2 = query(i, j, right(node), (a + b) / 2 + 1, b);
+ int mid = (a + b) / 2;
+ int q1 = query(i, j, left(node), a, mid);
+ int q2 = query(i, j, right(node), mid + 1, b);
return q1 + q2;
}
};
diff --git a/algorithms/structure/segment_tree.cpp b/algorithms/structure/segment_tree.cpp
index 568384c..6367e56 100644
--- a/algorithms/structure/segment_tree.cpp
+++ b/algorithms/structure/segment_tree.cpp
@@ -6,11 +6,11 @@
/// Query -> O(log n)
/// Complexity (Space): O(n)
+int N;
struct SegmentTree {
- int N;
vector<int> tree;
- SegmentTree(int N, const vector<int> &v) : N(N), tree(N*4) {
+ SegmentTree(const vector<int> &v) : tree(MAX*4) {
init();
build(v);
}
@@ -33,9 +33,10 @@ struct SegmentTree {
return;
}
- build(v, left(node), a, (a + b) / 2);
- build(v, right(node), 1 + (a + b) / 2, b);
- tree[node] = tree[node * 2] + tree[node * 2 + 1];
+ int mid = (a + b) / 2;
+ build(v, left(node), a, mid);
+ build(v, right(node), mid + 1, b);
+ tree[node] = tree[left(node)] + tree[right(node)];
}
/// Updates position idx by adding value val.
@@ -50,9 +51,10 @@ struct SegmentTree {
return;
}
- update(idx, val, left(node), a, (a + b) / 2);
- update(idx, val, right(node), 1 + (a + b) / 2, b);
- tree[node] = tree[node * 2] + tree[node * 2 + 1];
+ int mid = (a + b) / 2;
+ update(idx, val, left(node), a, mid);
+ update(idx, val, right(node), mid + 1, b);
+ tree[node] = tree[left(node)] + tree[right(node)];
}
/// Returns sum of [i,j].
@@ -64,8 +66,9 @@ struct SegmentTree {
if (i <= a && b <= j)
return tree[node];
- int q1 = query(i, j, left(node), a, (a + b) / 2);
- int q2 = query(i, j, right(node), 1 + (a + b) / 2, b);
+ int mid = (a + b) / 2;
+ int q1 = query(i, j, left(node), a, mid);
+ int q2 = query(i, j, right(node), mid + 1, b);
return q1 + q2;
}
};
--
GitLab