diff options
-rw-r--r-- | Year_2/Algorithms/matrix-chain.cc | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/Year_2/Algorithms/matrix-chain.cc b/Year_2/Algorithms/matrix-chain.cc new file mode 100644 index 0000000..2b87082 --- /dev/null +++ b/Year_2/Algorithms/matrix-chain.cc @@ -0,0 +1,75 @@ +#include <fstream> +#include <iostream> +#include <vector> +#define INF 9999999 + +using namespace std; + +using pii = pair<int, int>; + +int +matrix_chain_multiply(vector<pii> a) +{ + int n = a.size(); + int i, d, k; + + int** m = new int*[n]; + + for (i = 0; i < n; ++i) + m[i] = new int[n]; + + for (i = 0; i < n; ++i) + m[i][i] = 0; + + for (d = 1; d < n; ++d) { + for (i = 1; i < n - d; ++i) { + int j = d + i; + m[i][j] = INF; + + for (k = i; k < j; ++k) { + int q = m[i][k] + m[k + 1][j] + a[i - 1].first * a[k].first * a[j].first; + if (q < m[i][j]) + m[i][j] = q; + } + } + } + + int result = m[1][n - 1]; + + for (i = 0; i < n; ++i) + delete[] m[i]; + + delete[] m; + + return result; +} + +int +main(int argc, char** argv) +{ + int ts = (argc > 1) ? stoi(argv[1]) : 100; + ifstream fin("input.txt"); + ofstream fout("output.txt"); + string ch; + + for (int i = 0; i < ts; ++i) { + vector<pii> v; + int n, x1, x2 {}; + fin >> n; + + for (int j = 0; j < n; ++j) { + fin >> ch; + auto x = ch.find('x'); + x1 = stoi(ch.substr(1, x - 1)); + x2 = stoi(ch.substr(x + 1, ch.length() - 1)); + v.push_back({ x1, x2 }); + } + v.push_back({ x2, 0 }); + fout << matrix_chain_multiply(v) << endl; + } + + fin.close(); + fout.close(); + + return 0; +} |