PAT A1067. Sort with Swap(0,*) (25)

Given any permutation of the numbers {0, 1, 2,..., N-1}, it is easy to sort them in increasing order. But what if Swap(0, *) is the ONLY Operation that is allowed to use? For example, to sort {4, 0, 2, 1, 3} we may apply the swap operations in the following way:

Swap(0, 1) => {4, 1, 2, 0, 3}Swap(0, 3) => {4, 1, 2, 3, 0}Swap(0, 4) => {0, 1, 2, 3, 4}

Now you are asked to find the minimum number of swaps need to sort the given permutation of the first N nonnegative integers.

Input Specification:

Each input file contains one test case, which gives a positive N (<=10⁵) followed by a permutation sequence of {0, 1, ..., N-1}. All the numbers in a line are separated by a space.

Output Specification:

For each case, simply PRint in a line the minimum number of swaps need to sort the given permutation.

10 3 5 7 2 6 4 9 0 8 1Sample Output:
9
#include <cstdio>#include <algorithm>#include <cmath>#include <cstring>#include <map>#include <string>#define Max 100010using namespace std;int main(){	int n,S[Max];	scanf("%d",&n);	int f=n-1;	int m=0,l;	for(int i=0;i<n;i++)	{		scanf("%d",&S[i]);		if(S[i]==i) f--;	}	while(f>0)	{		if(S[0]==0)   //0在本位		{			int k=1;			while(k<n)			{				if(S[k]!=k)				{					swap(S[0],S[k]);					m++;					break;				}				k++;			}		}		else if(S[0]!=0)		{			swap(S[0],S[S[0]]);		    m++;			f--;		}	}	printf("%d/n",m);    system("pause");	return 0;}