【C++FAQ】怎么给结构体排序

使用stl中的sort,并重载要排序的结构体或类的<号即可。示例代码如下(pku1007题)

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <map>
#include <cmath>
using namespace std;

//只有ACGT这几个数
class DNAStr
{
public:
	bool operator < (const DNAStr& other) const{
		if (inversions < other.inversions)
		{
			return true;
		}
		if (inversions > other.inversions)
		{
			return false;
		}
		return _idx < other._idx;
	}
	DNAStr(string str,int idx)
	{
		_str = str;
		_idx = idx;
		int len = str.size();
		inversions = 0;
		char DNAChars[] = {'A','C','G','T'};
		for (int k = 0;k<4;k++)
		{
			int nLargerNum = 0;

			for (int i = 0;i<len;i++)
			{
				if (str[i] > DNAChars[k])
				{
					nLargerNum ++;
				}else if (str[i] == DNAChars[k])
				{
					inversions += nLargerNum;
				}
			}
		}
	}
	string _str;
	int _idx;
	int inversions; // 逆对数的对数
};
int main()
{
	vector<DNAStr> dnaStrs;
	int n,m;
	cin >> n >> m;
	for (int i = 0;i<m;i++)
	{
		string str;
		cin >> str;
		DNAStr dnaStr(str,i);
		dnaStrs.push_back(dnaStr);
	}

	sort(dnaStrs.begin(),dnaStrs.end());

	for (int i = 0;i<m;i++)
	{
		cout << dnaStrs[i]._str << endl;
	}
	return 0;
}