Question

因此，在给定gridView.setAdapter(customAdopter); customAdopter.setItemClickListener(new ItemClickListener() { @Override public void onItemClick(int position) { Intent intent = new Intent(MainActivity.this, SwipeView.class); intent.putExtra("id", position); startActivity(intent); } });列表和vector<unsigned>（这是找到子集总和的总和）时，我很难返回vector<unsigned> universal。

我尝试实现的给教授的伪代码是：

unsigned target

要弄清代码，请执行以下操作：subset_sum_dp(U[0...n-1], t): T = new 2D array with n+1 rows and t+1 columns, each element initialized to None for i from 0 through n: T[i][0] = [] for i from 1 through n: x = U[i-1] for j from 0 through t: if T[i-1][j] is not None: T[i][j] = T[i-1][j] else if T[i-1][j - x] is not None: T[i][j] = T[i-1][j - x] + [x] else: T[i][j] = None return T[n][t]正在串联列表。

我认为我最困惑的问题是将向量设置为空并将向量设置为T[i-1][j-x] + [x]。在None和T[i][0] = []行中，因为在将向量设置为T[i][j] = None时不断出现错误。

给出的给定骨架代码为：

NULL

到目前为止，我所实施的使我有所进步的是：

#pragma once

#include <optional>
#include <vector>

namespace subsetsum {

using natural_vector = std::vector<unsigned>;

// Solve the subset sum problem: return subset of universe that adds
// up to exactly target. If no such subset exists, return an empty optional.
// In the special case that target is zero, return an empty vector.
// universe must not be empty.
// This uses a dynamic programming search algorithm that takes pseudopolynomial
// time.
std::optional<natural_vector>
subset_sum_dp(const natural_vector& universe, unsigned target) {

  assert(!universe.empty());

  // TODO: Rewrite the body of this function so that it actually works. That
  // includes rewriting the return statement. After you do that, delete this
  // comment.

  return std::nullopt;
}

}

无论如何将vector设置为null来解决动态编程子集和问题？

0 个答案: