// https://dashoj.com/p/77

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

struct g {
    ll m; // 重量
    ll u; // 价值
    double x; // 每一重的价值
};

ll n, t;
vector<g> gs;

int main() {
    cin >> n >> t;
    for (int i = 0; i < n; i++) {
        ll m, u;
        cin >> m >> u;
        gs.push_back({m, u});
        gs[i].x = (double) u / (double) m;
    }
    sort(gs.begin(), gs.end(), [](g a, g b) {
        return a.x > b.x; // 按价值 / 重量从大到小排序
    });
    double ans = 0; // 答案
    for (int i = 0; i < n; ++i) {
        if (t >= gs[i].m) {
            t -= gs[i].m;
            ans += gs[i].u;
        } else {
            ans += t * gs[i].x;
            break;
        }
    }
    printf("%.2lf", ans);
    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct Coin {
    int weight;
    int value;
    double density;//价值密度
};

bool compareDensity(const Coin& a, const Coin& b) {
    return a.density > b.density;
}

int main() {
    int N, T;
    cin >> N >> T;
    vector<Coin> coins(N);

    for (int i = 0; i < N; i++) {
        cin >> coins[i].weight >> coins[i].value;
        coins[i].density = (double)coins[i].value / coins[i].weight;
    }

    sort(coins.begin(), coins.end(), compareDensity);

    double totalValue = 0.0;
    int remainingWeight = T;

    for (int i = 0; i < N && remainingWeight > 0; i++) {
        if (coins[i].weight <= remainingWeight) {
            totalValue += coins[i].value;
            remainingWeight -= coins[i].weight;
        } else {
            totalValue += coins[i].density * remainingWeight;
            remainingWeight = 0;
        }
    }

    printf ("%.2f", totalValue);
}

#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
struct node
{
int m,v;
double x;
};
bool cmp(node &a,node &b)
{
    if(a.x>b.x)
    return 1;
    return 0;
}
vector<node> vec;
int main()
{
int N,T,m,v;
double x;
cin>>N>>T;
for(int i=0;i<N;i++)
{
    cin>>m>>v;
    x=(double)v/(double)m;
vec.push_back({m,v,x});
}
double sum=0.0;
sort(vec.begin(),vec.end(),cmp);
for(int i=0;i<N;i++)
{
    if(T==0)
    break;
    if(T>=vec[i].m)
    {
sum+=vec[i].v;
T-=vec[i].m;
    }
    else{
        sum+=T*vec[i].x;
        T=0;
    }
}
printf("%.2lf",sum);
}

70%,不知道哪里错了，有佬能帮看看嘛

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

struct Gold
{
    int m;
    int v;
    double aver;
    bool operator<(const Gold& other) const
    {
        return aver < other.aver;
    }
};

int main()
{
    int N, T;
    int m, v;
    cin >> N >> T;
    double sum = 0;
    priority_queue<Gold> q;

    for(int i = 0; i < N; i++)
    {
        cin >> m >> v;
        q.push({m, v, (double)v/m});
    }

    while(T > 0)
    {
        Gold g = q.top();
        q.pop();
        // 背包能装下现在的所有金币
        if(T > g.m)
        {
            sum += g.v;
        }
        else
        {
            sum += T * g.aver;
        }
        T -= g.m;
    }

    printf("%.2lf", sum);
}

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

struct treasure{   //连锁数据排序
    double m, v, rate;
};

bool cmp(treasure a, treasure b)
{
    return a.rate>b.rate;
}

int main()
{
    int N, T;
    cin >> N >> T;
    vector<treasure> treasures(N);
    double sum=0;
    for(int i=0; i<N; i++)
    {
        cin >> treasures[i].m >> treasures[i].v;
        treasures[i].rate=treasures[i].v/treasures[i].m;
    }
    sort(treasures.begin(), treasures.end(), cmp);
    for(int i=0; i<N; i++)
    {
        if(T>=treasures[i].m)   //尽量不造成出现负数的情况
        {
            T-=treasures[i].m;
            sum+=treasures[i].v;
        }
        else
        {
            sum+=treasures[i].rate*T;
            T=0;
            break;
        }
    }
    printf("%.2lf", sum);
    return 0;
}

#include<iostream> #include<vector> #include<algorithm> #include<iomanip> using namespace std; struct gold { double value; double weight; double rate; }; bool cmp(const gold& t1,const gold& t2) { return t1.rate > t2.rate; } int main() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); int n, t; double numt = 0; double numv=0; vector<gold> v; cin >> n >> t; if (n < 0 || t < 0 || n>100 || t>1000)return 0; v.resize(n); for (int i = 0; i < n; i++) { cin >> v[i].weight >> v[i].value; if (v[i].value < 1 || v[i].weight < 1 || v[i].value>120)return 0; v[i].rate = v[i].value / v[i].weight; } sort(v.begin(),v.end(),cmp); int i = 0; while (numt <= t && i < n) { numt += v[i].weight;//可能会大于 numv += v[i].value; i++; } if (numt > t) { numv-=(numt - t)* v[i-1].rate; } cout << fixed<<setprecision(2)<<numv; return 0; }

#include<iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cstdio>
using namespace std;
const int N=102;
int n,zhilian;
struct gold{
	double weight;
	double worth;
	double every;
}go[N];
bool compair(gold a,gold b){
	return a.every>b.every;
}
int main(){
	cin>>n>>zhilian;
	int i=0;
	int t=n;
	while(t--){
		int x1,x2;
		scanf("%d%d",&x1,&x2);
		go[i].weight=x1,go[i].worth=x2;
		go[i].every=(double)x2/x1;
		i++;	
	}
	sort(go,go+n,compair);
	double res=0;
	for(int j=0;j<n;j++){
		if(zhilian>go[j].weight) res+=go[j].worth,zhilian-=go[j].weight;
		else {
			res+=go[j].every*zhilian;
			break;
		}
	}
	printf("%.2lf",res);
	return 0;
	
}

/上天啊 难道你看不出我很爱她/ #include<bits/stdc++.h> using namespace std; struct Node{ double m,v; double avg; }a[110]; bool cmp(Node x,Node y) { return x.avg>y.avg; } int main() { int n,t;cin>>n>>t; for(int i = 1;i<=n;i++) { cin>>a[i].m>>a[i].v; a[i].avg = a[i].v/a[i].m; } sort(a+1,a+1+n,cmp); double sum = 0; for(int i = 1;i<=n;i++) { if(t>=a[i].m) { sum = sum+a[i].v; t = t-a[i].m; } else { sum = sum+t1.0a[i].avg; break; } } cout<<fixed<<setprecision(2)<<sum; }