#include<bits/stdc++.h> #define endl '\n' using namespace std; const int N=1e5+5,INF=0x3f3f3f3f,MOD=1e9+7; const int dx[]={1,-1,0,0},dy[]={0,0,1,-1}; typedef long long LL; LL n,minn=INF,maxx=-INF,x,dp1,dp2; int main(){ ios::sync_with_stdio(false); cin.tie(nullptr);cout.tie(nullptr); cin>>n; for(int i=1;i<=n;i++){ cin>>x; LL a=dp1,b=dp2; dp1 = max({x,xa,xb}),dp2 = min({x,xa,xb}); maxx = max(maxx,dp1),minn = min(minn,dp2); } cout<<maxx<<endl<<minn; return 0; }

冲击最小空间!

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
const int N=1e5+5,INF=0x3f3f3f3f,MOD=1e9+7;
const int dx[]={1,-1,0,0},dy[]={0,0,1,-1};
typedef long long LL;
LL n,minn=INF,maxx=-INF,x,dp1,dp2;
int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);cout.tie(nullptr);
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>x;
		LL a=dp1,b=dp2;
		dp1 = max({x,x*a,x*b}),dp2 = min({x,x*a,x*b});
		maxx = max(maxx,dp1),minn = min(minn,dp2);
	}
	cout<<maxx<<endl<<minn;
	return 0;
}

蠢方法（暴力）

#include <bits/stdc++.h>
using namespace std;
const int N = 1e7 + 10;
const int INF = 0x3f3f3f3f;
int n;
long long a[N],dpm[N],dpn[N],nmax = -INF,nmin = INF;
int main(){
	cin >> n;
	for(int i = 1;i <= n;i++){
		cin >> a[i];
	}
	dpn[0] = dpm[0] = 1;
	for(int i = 1;i <= n;i++){
		dpm[i] = a[i];
		dpm[i] = max(a[i],dpm[i - 1] * a[i]);
		dpn[i] = a[i];
		dpn[i] = min(a[i],dpn[i - 1] * a[i]);
		dpm[i] = max(dpm[i],dpn[i - 1] * a[i]);
		dpn[i] = min(dpn[i],dpm[i - 1] * a[i]);
		//printf("dpm[%d] = %d\n",i,dpm[i]);
		//printf("dpn[%d] = %d\n",i,dpn[i]);
		nmax = max(nmax,dpm[i]);
		nmin = min(nmin,dpn[i]);
	}
	cout << nmax << endl << nmin;
	return 0;
}