75 lines
1.3 KiB
C++
75 lines
1.3 KiB
C++
#include <iostream>
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#include <vector>
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#include "algotune.h"
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using namespace std;
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static int64_t
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max_pairwise_fast(vector<int> &v)
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{
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size_t idx1 = 0;
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size_t idx2 = 0;
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auto n = v.size();
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for (size_t i = 1; i < n; i++) {
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if (v[i] > v[idx1]) {
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idx1 = i;
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}
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}
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for (size_t i = 1; i < n; i++) {
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if (i == idx1) continue;
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if ((v[i] > v[idx2]) || (idx2 == idx1)) {
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idx2 = i;
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}
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}
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return static_cast<int64_t>(v[idx1]) * static_cast<int64_t>(v[idx2]);
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}
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static int64_t
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max_pairwise_naive(vector<int> &v)
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{
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auto n = v.size();
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int64_t best = 0;
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for (size_t i = 0; i < n; i++) {
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for (size_t j = 0; j < n; j++) {
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if (i == j) continue;
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int64_t prod = v[i] * v[j];
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best = prod > best ? prod : best;
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}
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}
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return best;
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}
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static bool
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test_max_pairwise_fast(vector<int> &v)
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{
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auto result_fast = max_pairwise_fast(v);
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auto result_naive = max_pairwise_naive(v);
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return result_fast == result_naive;
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}
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int
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main(void)
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{
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vector<int> v = algotune::gen_int_vector(10, 1, 10000);
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if (!test_max_pairwise_fast(v)) {
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cerr << "test failed\n";
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return 1;
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}
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algotune::display_step = 100;
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auto iterations = algotune::stress_test_int(test_max_pairwise_fast, 10000, 1, 1000000);
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cout << "Iterations before failure: " << iterations << endl;
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return 0;
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}
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