我正在尝试使用合并排序来对字符串中的所有字符进行排序。但是我总是遇到一些编译问题。具体来说,我在以下方面遇到问题:[if(s [i1] .compare(s [i2])<0)]和[s [from + j] = b [j];]。有什么帮助吗?
void mergeSort(string &s, int from, int to)
{
if (from == to)
{
return;
}
int mid = (from + to) / 2;
mergeSort(s, from, mid);
mergeSort(s, mid + 1, to);
merge(s, from, mid, to);
}
void merge(string &s, int from, int mid, int to)
{
int n = to - from + 1;
vector<string> b(n); // merge both halves into a temporary vector b
int i1 = from;
int i2 = mid + 1;
int j = 0;
while (i1 <= mid && i2 <= to)
{
if (s[i1].compare(s[i2]) < 0)
{
b[j] = s[i1];
i1++;
}
else
{
b[j] = s[i2];
i2++;
}
j++;
}
// copy any remaining entries of the first half
while (i1 <= mid)
{
b[j] = s[i1];
i1++;
j++;
}
// copy any remaining entries of the second half
while (i2 <= to)
{
b[j] = s[i2];
i2++;
j++;
}
// copy back from the temporary array
for (j = 0; j < n; j++)
{
s[from + j] = b[j];
}
}
int main(){
string str = "cdebfag"
if (str.length() >= 2 )
mergeSort(str, 0, str.length() - 1);
//print sorted
cout << str << endl;
return 0;
}
错误是:
对'(&s)-> std :: __ cxx11 :: basic_string :: operator'中成员'compare'的请求,它是非类类型'__gnu_cxx :: __ alloc_traits,char> :: value_type'{aka'炭'}
和
类型'std :: __ cxx11 :: string&'的引用的无效初始化{aka'std :: __ cxx11 :: basic_string&'}来自类型'std :: vector的表达式”
[s[i]
不是string
,而是char
,并且char
没有任何成员函数。
而不是:
if (s[i1].compare(s[i2]) < 0)
您应该尝试类似:
if (s[i1] < s[i2])
除了Sid的答案,您还应该输入vector<char> b
而不是vector<string> b
。