c++17/c++20以上代码

#include<bits/stdc++.h>
using namespace std;
using i64 = long long;

void solve(i64 n,i64 x, i64 y, vector<int>a){
    i64 sum = reduce(a.begin(),a.end());
    i64 l = sum -y,r =sum-x;
    ranges::sort(a);
    int x1 = n-1, x2=n-1;
    i64 res = 0;
    for (int i = 0;i<n;i++){
        i64 t1 = l-a[i],t2=r-a[i];
        while (x2>i && a[x2]>t2)x2--;
        if (x2<=i) continue;
        x1=min(x1,x2);
        x1=max(x1,i+1);
        while(x1>i && a[x1]>=t1)x1--;
        if (x1+1 < n && a[x1+1]>=t1 && x2-x1 >0 && x1>=i &&x2>i){
            res +=x2 - x1;
        }
    }
    cout << res << endl;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;

    while (t--) {
        i64 n, x, y;
        cin >> n >> x>> y;
        vector<int> a(n);
        for (int i = 0; i < n; ++i) {
            cin >> a[i];
        }
        solve(n,x,y,a);
    }
    return 0;
}

rust代码

use crate::algo_lib::collections::iter_ext::iters::Iters;
use crate::algo_lib::collections::min_max::MinimMaxim;
use crate::algo_lib::collections::vec_ext::default::default_vec;
use crate::algo_lib::collections::vec_ext::gen::VecGen;
use crate::algo_lib::io::input::Input;
use crate::algo_lib::io::output::Output;
use crate::algo_lib::misc::extensions::do_with::DoWith;
use crate::algo_lib::misc::test_type::TaskType;
use crate::algo_lib::misc::test_type::TestType;
// https://codeforces.com/submissions/Egor 感谢这位大佬的代码
use std::fs::File;
use std::io::BufReader;
//use std::collections::HashSet;
use std::cmp;
type PreCalc = ();
//这个模板里会把N读成第一个.然后每个样例读。
fn solve(input: &mut Input, out: &mut Output, _test_case: usize, _data: &mut PreCalc) {
    let n = input.read_size(); 
    let x: usize = input.read_size(); 
    let y = input.read_size() as i64; 
    let mut a = input.read_long_vec(n);
    //let mut ans = vec![0;n];
    let mut res = 0;
    //let mut books = HashSet::new();
    //let mut unbooks = HashSet::new();
    let sum: i64 = a.iter().sum();
    let l = sum - y;
    let r = sum - x as i64;
    a.sort();
    let mut x1 = n - 1;
    let mut x2 = n - 1;
    let mut res = 0;
    for i in 0..n {
        let t1 = l - a[i as usize];
        let t2 = r - a[i as usize];
        while x2 > i && a[x2 as usize] > t2 {
            x2 -= 1;
        }
        if x2 <= i { continue; }
        x1 = cmp::min(x1, x2);
        x1 = cmp::max(x1, i + 1);
        while x1 > i && a[x1 as usize] >= t1 {
            x1 -= 1;
        }
        if x1 + 1 < n && a[(x1 + 1) as usize] >= t1 && x2 - x1 > 0 && x1 >= i && x2 > i {
            res += x2 - x1;
        }
    }
    //println!("{}", res);
    out.print_line(res);
} 

fn main() {
    //Local-testing 本地测试可以读src文件夹下input.txt作为输入数据
    //let file = File::open("src/input.txt").expect("Failed to open input file");
    //let mut sin = BufReader::new(file);
    let mut sin = std::io::stdin(); //线上编译器会传入在stdin里
    let input = crate::algo_lib::io::input::Input::new(&mut sin);
    let mut stdout = std::io::stdout();
    let output = crate::algo_lib::io::output::Output::new(&mut stdout);
    run(input, output);
}

还有其他模板：

https://www.acwing.com/solution/content/262489/ 把模板拼到rust算法后面！

https://www.acwing.com/solution/content/262489/