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improve checker complexity

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This commit is contained in:
Laurent Perron
2023-07-10 14:38:31 +02:00
parent 2a07d256f2
commit 30e58583ad
1 changed files with 35 additions and 33 deletions
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68
ortools/flatzinc/checker.cc
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@@ -19,6 +19,7 @@
#include <functional>
#include <limits>
#include <string>
#include <utility>
#include <vector>
#include "absl/container/flat_hash_map.h"
@@ -386,62 +387,63 @@ bool CheckDiffnNonStrictK(
bool CheckDisjunctive(const Constraint& ct,
const std::function<int64_t(Variable*)>& evaluator) {
// TODO(user): Improve complexity for large size.
const int size = Size(ct.arguments[0]);
CHECK_EQ(size, Size(ct.arguments[1]));
absl::flat_hash_map<int64_t, int64_t> usage;
for (int i = 0; i < size; ++i) {
const int64_t start = EvalAt(ct.arguments[0], i, evaluator);
std::vector<std::pair<int64_t, int64_t>> start_durations_pairs;
start_durations_pairs.reserve(size);
for (int i = 0; i + 1 < size; ++i) {
const int64_t duration = EvalAt(ct.arguments[1], i, evaluator);
for (int64_t t = start; t < start + duration; ++t) {
++usage[t];
if (usage[t] > 1) {
return false;
}
}
if (duration == 0) continue;
const int64_t start = EvalAt(ct.arguments[0], i, evaluator);
start_durations_pairs.push_back({start, duration});
}
std::sort(start_durations_pairs.begin(), start_durations_pairs.end());
int64_t previous_end = std::numeric_limits<int64_t>::min();
for (const auto& pair : start_durations_pairs) {
if (pair.first < previous_end) return false;
previous_end = pair.first + pair.second;
}
return true;
}
bool CheckDisjunctiveStrict(
const Constraint& ct, const std::function<int64_t(Variable*)>& evaluator) {
// TODO(user): Improve complexity for large size.
const int size = Size(ct.arguments[0]);
CHECK_EQ(size, Size(ct.arguments[1]));
std::vector<std::pair<int64_t, int64_t>> start_durations_pairs;
start_durations_pairs.reserve(size);
for (int i = 0; i + 1 < size; ++i) {
const int64_t start_i = EvalAt(ct.arguments[0], i, evaluator);
const int64_t duration_i = EvalAt(ct.arguments[1], i, evaluator);
for (int j = i + 1; j < size; ++j) {
const int64_t start_j = EvalAt(ct.arguments[0], j, evaluator);
const int64_t duration_j = EvalAt(ct.arguments[1], j, evaluator);
if (start_i + duration_i <= start_j || start_j + duration_j <= start_i) {
continue;
}
return false;
}
const int64_t start = EvalAt(ct.arguments[0], i, evaluator);
const int64_t duration = EvalAt(ct.arguments[1], i, evaluator);
start_durations_pairs.push_back({start, duration});
}
std::sort(start_durations_pairs.begin(), start_durations_pairs.end());
int64_t previous_end = std::numeric_limits<int64_t>::min();
for (const auto& pair : start_durations_pairs) {
if (pair.first < previous_end) return false;
previous_end = pair.first + pair.second;
}
return true;
}
bool CheckDisjunctiveStrictOpt(
const Constraint& ct, const std::function<int64_t(Variable*)>& evaluator) {
// TODO: Improve complexity for large size.
const int size = Size(ct.arguments[0]);
CHECK_EQ(size, Size(ct.arguments[1]));
CHECK_EQ(size, Size(ct.arguments[2]));
std::vector<std::pair<int64_t, int64_t>> start_durations_pairs;
start_durations_pairs.reserve(size);
for (int i = 0; i + 1 < size; ++i) {
if (EvalAt(ct.arguments[0], i, evaluator) == 0) continue;
const int64_t start_i = EvalAt(ct.arguments[1], i, evaluator);
const int64_t duration_i = EvalAt(ct.arguments[2], i, evaluator);
for (int j = i + 1; j < size; ++j) {
if (EvalAt(ct.arguments[0], j, evaluator) == 0) continue;
const int64_t start_j = EvalAt(ct.arguments[1], j, evaluator);
const int64_t duration_j = EvalAt(ct.arguments[2], j, evaluator);
if (start_i + duration_i <= start_j || start_j + duration_j <= start_i) {
continue;
}
return false;
}
const int64_t start = EvalAt(ct.arguments[1], i, evaluator);
const int64_t duration = EvalAt(ct.arguments[2], i, evaluator);
start_durations_pairs.push_back({start, duration});
}
std::sort(start_durations_pairs.begin(), start_durations_pairs.end());
int64_t previous_end = std::numeric_limits<int64_t>::min();
for (const auto& pair : start_durations_pairs) {
if (pair.first < previous_end) return false;
previous_end = pair.first + pair.second;
}
return true;
}