CF #324 DIV2 E题

这题很简单，把目标位置排序，把目标位置在当前位置前面的往前交换，每次都是贪心选择第一个满足这样要求的数字。

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;

const int MAX=2005;

int p1[MAX],p2[MAX],mp[MAX];
int pos[MAX],goal[MAX];
bool rip[MAX];

vector<pair<int,int> >ans;

int main(){
	int n,counts,ans_counts,cost;
	while(scanf("%d",&n)!=EOF){
		counts=0;
		ans.clear();
		cost=0;
		for(int i=1;i<=n;i++) scanf("%d",&p1[i]);
		for(int i=1;i<=n;i++){
			scanf("%d",&p2[i]);
			mp[p2[i]]=i;
		}
		for(int i=1;i<=n;i++){
			if(p1[i]!=p2[i]){
				pos[++counts]=i;
				goal[counts]=mp[p1[i]];
			}
		}
/*		for(int i=1;i<=counts;i++)
			cout<<pos[i]<<" ";
		cout<<endl;
		for(int i=1;i<=counts;i++){
			cout<<goal[i]<<" ";
		}
		cout<<endl;*/
		memset(rip,false,sizeof(rip));
		if(counts==0){
			puts("0");
			puts("0");
			continue;
		}
		int lmin=1;
		for(int i=1;i<=counts;i++){
			if(goal[i]<pos[i]){
				int rmax=i-1,last=i,g=goal[i];
				while(pos[last]!=g){
					if(!rip[rmax]){
						ans.push_back(make_pair(pos[last],pos[rmax]));
						swap(goal[last],goal[rmax]);
						if(goal[last]==pos[last]) rip[last]=true;
						cost+=abs(pos[last]-pos[rmax]);
						last=rmax;
					}
					rmax--;
				}
				rip[last]=true;
				for(;;lmin++) if(!rip[lmin]) break;
			}
		}
		printf("%d\n",cost);
		printf("%d\n",ans.size());
		int sz=ans.size();
		for(int i=0;i<sz;i++){
			printf("%d %d\n",ans[i].first,ans[i].second);
		}
	}
	return 0;
}