暴力

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
void solve();

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int t=1;
//	cin>>t;
	while(t--){
		solve();
	}
	return 0;
}

void solve(){
	int n;
	cin>>n;
	vector<vector<int>> co(n+1,vector<int>(256));
	vector<int>a(n+1);
	string s;
	for(int i=1;i<=n;i++){
		cin>>s;
		a[i]=s.size();
		for(auto c:s)
			co[i][c]++;
	}
	ll ans=0;
	for(int i=1;i<=n;i++){
		for(int j=i+1;j<=n;j++){
			bool f=1;
			for(int k='a';k<='z';k++){
				if(co[i][k]&&co[j][k])
					f=0;
			}
			if(f)
				ans=max(ans,1ll*a[i]*a[j]);
		}
	}
	cout<<ans<<endl;
	
}

暴力枚举

import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[][] arr = new int[n][27];

        for (int i = 0; i < arr.length; i++) {
            String str = sc.next();
            arr[i][26] = str.length();
            for (int j = 0; j < str.length(); j++) {
                arr[i][str.charAt(j) - 'a']++;
            }
        }
        int ans = 0;
        Arrays.sort(arr, (o1, o2) -> (o2.length - o1.length));
        for (int i = 0; i < arr.length; i++) {
            int j = i + 1;
            for (; j < arr.length; j++) {
                if(!cal(arr[i], arr[j])){
                    ans = Math.max(ans, arr[i][26] * arr[j][26]);
                }
            }
        }
        System.out.println(ans);
    }
    public static boolean cal(int[] a, int[] b){
        for (int i = 0; i < 26; i++) {
            if(a[i] > 0 && b[i] > 0) return true;
        }
        return false;
    }
}

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] a = new int[n];
        int[] b = new int[n];
        // 遍历数组a
        for (int i = 0; i < n; i++) {
            String word = sc.next();
            b[i] = word.length();
            // 遍历字符串
            for (int j = 0; j < word.length(); j++) {
                int c = word.charAt(j) - 'a';
                a[i] |= 1 << c;
            }
        }
        int num = 0;
        for (int i = 0; i < a.length; i++) {
            for (int j = i; j < a.length; j++) {
                if ((a[i] & a[j]) == 0) {
                    num = Math.max(num, b[i] * b[j]);
                }
            }
        }
        System.out.println(num);
    }
}

用二进制的位来表示字母

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

int main() {
// 注意：在C++中，主函数必须返回一个int类型
int n;
cin >> n;
vector<int> a(n), b(n);
for (int i = 0; i < n; i++) {
string word;
cin >> word;
b[i] = word.length();
for (char c : word) {
a[i] |= 1 << (c - 'a');
}
}
int num = 0;
for (int i = 0; i < a.size(); i++) {
for (int j = i; j < a.size(); j++) {
if ((a[i] & a[j]) == 0) {
num = max(num, b[i] * b[j]);
}
}
}
cout << num << endl;
return 0;
}