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Return optional<int> from segment tree binary search methods #157

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Merged
ei1333 merged 4 commits into from
Nov 21, 2025
Merged

Return optional<int> from segment tree binary search methods #157

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6d37abb
Initial plan
Copilot Nov 20, 2025
7fcfe28
Modify find_first and find_last to return optional<int>
Copilot Nov 20, 2025
a0e9427
Final verification complete
Copilot Nov 20, 2025
e829ae7
Remove CodeQL artifact
Copilot Nov 20, 2025
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12 changes: 6 additions & 6 deletions structure/segment-tree/lazy-segment-tree.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -116,8 +116,8 @@ struct LazySegmentTree {
}

template <typename C>
int find_first(int l, const C& check) {
if (l >= n) return n;
optional<int> find_first(int l, const C& check) {
if (l >= n) return nullopt;
l += sz;
for (int i = height; i > 0; i--) propagate(l >> i);
S sum = m.e();
Expand All @@ -137,12 +137,12 @@ struct LazySegmentTree {
}
sum = m.op(sum, data[l++]);
} while ((l & -l) != l);
return n;
return nullopt;
}

template <typename C>
int find_last(int r, const C& check) {
if (r <= 0) return -1;
optional<int> find_last(int r, const C& check) {
if (r <= 0) return nullopt;
r += sz;
for (int i = height; i > 0; i--) propagate((r - 1) >> i);
S sum = m.e();
Expand All @@ -163,6 +163,6 @@ struct LazySegmentTree {
}
sum = m.op(data[r], sum);
} while ((r & -r) != r);
return -1;
return nullopt;
}
};
12 changes: 6 additions & 6 deletions structure/segment-tree/segment-tree.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -66,8 +66,8 @@ struct SegmentTree {
S all_prod() const { return seg[1]; }

template <typename C>
int find_first(int l, const C& check) const {
if (l >= n) return n;
optional<int> find_first(int l, const C& check) const {
if (l >= n) return nullopt;
l += sz;
S sum = m.e();
do {
Expand All @@ -85,12 +85,12 @@ struct SegmentTree {
}
sum = m.op(sum, seg[l++]);
} while ((l & -l) != l);
return n;
return nullopt;
}

template <typename C>
int find_last(int r, const C& check) const {
if (r <= 0) return -1;
optional<int> find_last(int r, const C& check) const {
if (r <= 0) return nullopt;
r += sz;
S sum = m.e();
do {
Expand All @@ -109,6 +109,6 @@ struct SegmentTree {
}
sum = m.op(seg[r], sum);
} while ((r & -r) != r);
return -1;
return nullopt;
}
};
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