P3475 [POI 2008] 模拟退火94pt求调
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  • 发布时间2025/8/29 16:09
  • 上次更新2025/8/29 21:43:12
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P3475 [POI 2008] 模拟退火94pt求调
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Mr_yeh楼主2025/8/29 16:09
#include<bits/stdc++.h>
using namespace std;
const double dlt=0.998;
const int N=30;
int n,m,x,y,mp[N][N],a[N],as[N],ans=0x3f;
int calm(){
	int sum=0;
	for(int i=1;i<=n/2;i++){
		for(int j=n/2+1;j<=n;j++){
			if(mp[a[i]][a[j]]) sum++;
		}
	}
	return sum;
}
void SA(){
	double bt=3000,et=1e-15;
	while(bt>et){
		int sr1=rand()%(n/2)+1,sr2=rand()%(n/2)+n/2+1;
		swap(a[sr1],a[sr2]);
		int res=calm();
		int diff=res-ans;
		if(diff<0){
			ans=res;
			for(int i=1;i<=n/2;i++) as[i]=a[i];
		}else if(exp(-1.0*diff/bt)*RAND_MAX<(double)rand()){
			swap(a[sr1],a[sr2]);
		}
		bt*=dlt;
	}
}
int main(){
	srand(time(0));
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++) a[i]=i;
	while(m--){
		cin>>x>>y;
		mp[x][y]=mp[y][x]=1;
	}
	ans=calm();
	while((double)clock()/CLOCKS_PER_SEC<0.95){
		SA();
	}
	sort(as+1,as+n/2+1);
	for(int i=1;i<=n/2;i++) cout<<as[i]<<" ";
	cout<<'\n';
	return 0;
}
2025/8/29 16:09
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