POJ 1007_DNA Sorting

  本題先求各個DNA序列的逆序數，再排序，這裏是穩定排序（題目中說明了如果二者逆序數相同不改變相對位置）。So，這裏用stable_sort(),not sort()。 之前一直wa，把輸入方式getline(cin,string **)改爲cin>>..結果AC了，that's strange !

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

struct DNA{							//save the DNA sequences
	char str[55];				
	int num;	
} dna[105];

int unsortedness(char *p){			//count the unsortedness measures
	int unsortNum = 0;
	for (int j = 1; j < strlen(p); j++){
		for (int k = 0; k < j; k++){
			if (p[k]>p[j])
				unsortNum++;
		}
	}
	return unsortNum;
}

bool cmp(DNA p1, DNA p2){				//	a parameter of  stable_sort
	return p1.num < p2.num;
}

int main()
{

	int i;
	int n, m;	     // n length of a string ,m lines
	cin >> n >> m;
	for (i = 0; i < m; i++){			//input test case 
		cin >> dna[i].str;
		dna[i].num = unsortedness(dna[i].str);		
	}

	stable_sort(dna, dna + m, cmp);		// not sort()

	for (i = 0; i < m;i++){				//display the sorted sequences
		cout << dna[i].str << endl;
	}

	return 0;
}