Files
DataStructureAndAlgorithm/2023210/main.cpp
2024-01-23 13:26:21 +01:00

143 lines
3.4 KiB
C++

#include <stdio.h>
struct CalcResult {
int dim_status;
int min_multiply_times;
};
unsigned short *tensors;
// unsigned short tensors[66000];
int n = 0, k = 0;
CalcResult *m;
// CalcResult m[10000];
// int* m;
int dim_sizes[32] = {0};
// int precalc[2][1048576] = {0};
int tensor_pos(int num, int dim) {
return k * num + dim;
}
int setm(int i, int j, int num) {
if (j <= i) {
return 0;
}
return m[(2 * n - i + 1) * i / 2 + j - i].min_multiply_times = num;
}
int getm(int i, int j) {
if (j <= i) {
return 0;
}
return m[(2 * n - i + 1) * i / 2 + j - i].min_multiply_times;
}
int setmdim(int i, int j, int d) {
if (j < i) {
return 0;
}
return m[(2 * n - i + 1) * i / 2 + j - i].dim_status = d;
}
int getmdim(int i, int j) {
if (j < i) {
return 0;
}
return m[(2 * n - i + 1) * i / 2 + j - i].dim_status;
}
int find_min(int start, int end) {
if (start == end || getm(start, end) != 0) {
return getm(start, end);
}
int min = 2147483647;
int needed_multiply_by_d = 1;
int dim_status = getmdim(start, end);
// prepare the dims
for (int i = 0; i < k - 2; i++) {
if ((dim_status >> i) & 1) {
needed_multiply_by_d *= dim_sizes[i];
}
}
// for (int i = 0; i <= (k - 2) / 16; i++) {
// needed_multiply_by_d *= precalc[i][(dim_status >> (16 * i)) & 0xffff];
// }
for (int split_pos = start; split_pos < end; split_pos++) {
int total_needed = tensors[tensor_pos(start, k - 2)] *
tensors[tensor_pos(split_pos, k - 1)] * tensors[tensor_pos(end, k - 1)] *
needed_multiply_by_d;
int left = find_min(start, split_pos), right = find_min(split_pos + 1, end);
total_needed += left + right;
if (total_needed < min) {
min = total_needed;
}
}
setm(start, end, min);
return min;
}
void preparedim(int length) {
if (length == 1) {
for (int i = 0; i < n; i++) {
int cur_stat = 0;
for (int j = 0; j < k - 2; j++) {
if (tensors[tensor_pos(i, j)] != 1) {
cur_stat |= 1 << j;
}
}
setmdim(i, i, cur_stat);
}
return;
}
preparedim(length - 1);
for (int i = length - 1; i < n; i++) {
setmdim(i - length + 1, i, getmdim(i - length + 1, i - 1) | getmdim(i, i));
}
}
int main() {
scanf("%d %d", &n, &k);
tensors = new unsigned short[n * k];
m = new CalcResult[(n + 1) * n / 2];
for (int i = 0; i < 32; i++) {
dim_sizes[i] = 1;
}
// m = new int[(n + 1) * n / 2];
for (int tensor_count = 0; tensor_count < n; tensor_count++) {
for (int dim = 0; dim < k; dim++) {
scanf("%hu", &tensors[tensor_pos(tensor_count, dim)]);
if (tensors[tensor_pos(tensor_count, dim)] != 1) {
dim_sizes[dim] = tensors[tensor_pos(tensor_count, dim)];
}
}
}
// for (int i = 0; i < 2; i++) {
// for (int j = 0; j < 0xffff; j++) {
// int prod = 1;
// for (int r = 0; r < 16; r++) {
// if ((j >> r) & 1) {
// prod *= dim_sizes[i * 16 + r];
// }
// }
// precalc[i][j] = prod;
// }
// }
preparedim(n);
printf("%d\n", find_min(0, n - 1));
return 0;
}