A30362.宝藏

疑似01背包，但是物品可以分割，所以是贪心

#include <iostream>
#include <iomanip>
#include <algorithm>
using namespace std;

int main() {
	cout.flags(ios::fixed);
	cout.precision(2);
	int k; cin >> k;
	while (k--) {
		int w, s;
		cin >> w >> s;
		struct thing {
			int w, v;
			double xjb;
			bool operator < (const thing &other) {
				return xjb > other.xjb;
			} 
		} things[105];
		for (int i=1; i<=s; i++) {
			cin >> things[i].w >> things[i].v;
			things[i].xjb = (double)things[i].v/things[i].w;
		}
		sort(things+1, things+s+1);
		double ans=0;
		for (int i=1; i<=s; i++) {
			if (w > things[i].w) {
				w -= things[i].w;
				ans += things[i].v;
			}else {
				ans += (double)w/things[i].w*things[i].v;
				break;
			}
		}
		cout << ans << endl;
	}
	return 0;
}