算法入门-排序算法

BGN25 小红书推荐系统

//
// Created by XIAOBAI on 2026/5/7.
//

#include <iostream>
#include<unordered_map>
#include<set>
#include<string>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <bitset>
#include <unordered_set>
#include <map>
using namespace std;
//小红书推荐系统
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;
using ll = long long;
using ull = unsigned long long;

bool cmp(int a,int b) {
    return a>b;
}
bool cmp1(pair<string,int> a,pair<string,int> b) {
    if (a.second!=b.second) return a.second>b.second;
    return a.first<b.first;
}

void solve() {
	map<string,int> a;
    vector<pair<string,int>> v;
    string s;
    while(cin>>s) {
        a[s]++;
    }
    for (auto& i:a) {
        v.push_back(i);
    }
    sort(v.begin(),v.end(),cmp1);
    for (auto i : v) {
        if (i.second >=3) {
            cout<<i.first<<'\n';
        }
    }
}


int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T=1;
    //cin>>T;
    while(T--) {
        solve();
    }

}

BGN27 谐距下标对

//
// Created by XIAOBAI on 2026/5/7.
//
//
// Created by XIAOBAI on 2026/5/7.
//

#include <iostream>
#include<unordered_map>
#include<set>
#include<string>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <bitset>
#include <unordered_set>
#include <map>
using namespace std;
//谐距下标对
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;
using ll = long long;
using ull = unsigned long long;
bool cmp(int a,int b) {
    return a>b;
}

bool cmp1(pair<string,int> a,pair<string,int> b) {
    if (a.second!=b.second) return a.second>b.second;
    return a.first<b.first;
}

void solve() {
    unordered_map<int,int> a;
    ll n,ans=0;
    cin>>n;
    vector<int> v(n);
    for(int i=0;i<n;i++) {
        cin>>v[i];
        if (!a[v[i]])a[v[i]]=1;
        else {ans+=a[v[i]];a[v[i]]++;}
    }
    cout<<ans;


}


int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T=1;
    //cin>>T;
    while(T--) {
        solve();
    }

}