Question

我正在尝试使用以下 unordered_map 结构。

#include <iostream>
#include <cstdlib>
#include <vector>
#include <cstring>
#include <string>
#include <unordered_map>

using namespace std;


int width = 6;
int length = 6;
string parameters[] = {"0 0 0 1","6 6 5 6"};

struct co_ord {
  int x,y;
  int x1, y1;
  co_ord(int x, int y, int x1, int y1) : x(x), y(y), x1(x1), y1(y1) {}
};

struct co_ordHash {
  size_t operator()(const co_ord& key) const {
    return ((10+key.x)*100000000) + ((10+key.y)*1000000) + ((10+key.x1)*10000) + ((10+key.y1)*100);
  }
};


struct co_ordEqual {
  bool operator()(const co_ord& lhs, const co_ord& rhs) const {
    return lhs.x == rhs.x && lhs.y == rhs.y && lhs.x1 == rhs.x1 && lhs.y1 == rhs.y1;
  }
};

int maxPath(int x, int y, unordered_map<co_ord, bool, co_ordHash, co_ordEqual> barriers) {
  // unordered_map<co_ord, bool>::const_iterator iter;
  int sum = 0;
  if (x > width || y > length) {
    return 0;
  }

  if (x==width && y==length) {
    return 1;
  }

  co_ord *temp;
  temp = new co_ord(x, y, x+1, y);
  unordered_map<co_ord, bool, co_ordHash, co_ordEqual>::const_iterator iter1 = barriers.find(*temp);
  if (iter1 == barriers.end()) {
    sum = maxPath(x+1, y, barriers);
  }
  temp = new co_ord(x, y, x, y+1);
  unordered_map<co_ord, bool, co_ordHash, co_ordEqual>::const_iterator iter2 = barriers.find(*temp);
  if (iter2 == barriers.end()) {
    return sum + maxPath(x, y+1, barriers);
  }
  return sum;
}

int main(int argc, char const *argv[]) {
  string barrier[4];
  string delimiter = " ";
  co_ord *temp;
  unordered_map<co_ord, bool, co_ordHash, co_ordEqual> barriers;

  int i,j,k, para_len = sizeof(parameters)/sizeof(parameters[0]);

  for (i = 0; i < para_len; i++) {
    j = k = 0;
    while (j<4) {
      barrier[j] = "";
      while (parameters[k] != " " || parameters[k]!= "\n") {
        barrier[j] += parameters[k];
        k++;
      }
      barrier[j] += '\n';
      j++;
    }
    temp = new co_ord(stoi(barrier[0]), stoi(barrier[1]), stoi(barrier[2]), stoi(barrier[3]));
    barriers.insert(temp, false); // here is the problem
  }

  cout<<maxPath(0,0, barriers);

  return 0;
}

我无法插入函数。任何人都可以帮助我吗？我收到这个错误：

    avoidroads_dp.cc:79:14: error: no matching member function for call to 'insert'
    barriers.insert(temp, false);
    ~~~~~~~~~^~~~~~
1 error generated.

Answer 1

使用std :: make_pair插入数据。还有一件事：根据您的模板签名，您使用co_ord类型作为键，但您尝试添加指向co_ord对象的指针。您应该使用指针作为键来更改签名或拒绝。

这是一个固定字符串的例子

barriers.insert(make_pair(*temp, false));

插入不在cpp中的自定义散列函数中工作unordered_map

1 个答案: