題解

感謝小迪給我講題啊，這題小迪寫挺好的我就不寫了吧
小迪的題解

代碼

#include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #include <ctime> #include <vector> #include <set> //#define ivorysi #define eps 1e-8 #define mo 974711 #define pb push_back #define mp make_pair #define pii pair<int,int> #define fi first #define se second #define MAXN 10005 #define space putchar(' ') #define enter putchar('\n') using namespace std; typedef long long int64; typedef unsigned int u32; typedef unsigned long long u64; typedef double db; const int64 MOD = 1000000007; template<class T> void read(T &res) {res = 0;char c = getchar();T f = 1;while(c < '0' || c > '9') {if(c == '-') f = -1;c = getchar();}while(c >= '0' && c <= '9') {res = res * 10 + c - '0';c = getchar();}res *= f; } template<class T> void out(T x) {if(x < 0) putchar('-');if(x >= 10) {out(x / 10);}putchar('0' + x % 10); } int N; db E,s[MAXN],k[MAXN],v[MAXN]; db getv(db x,int id) {db l = max(0.0,v[id]),r = 100000;int cnt = 50;db t = -1 / x;while(cnt--) {db mid = (l + r) / 2;if(mid * mid * (mid - v[id]) * 2 * k[id] <= t) l = mid;else r = mid;}return l; } db calc(db x) {db res = 0;for(int i = 1 ; i <= N ; ++i) {db t = getv(x,i);res += k[i] * s[i] * (t - v[i]) * (t - v[i]);}return res; } void Solve() {scanf("%d%lf",&N,&E);for(int i = 1 ; i <= N ; ++i) {scanf("%lf%lf%lf",&s[i],&k[i],&v[i]);}int cnt = 100;db L = -100000,R = 0;while(cnt--) {db MID = (L + R) / 2;if(calc(MID) <= E) L = MID;else R = MID;}db ans = 0;for(int i = 1 ; i <= N ; ++i) {ans += s[i] / getv(L,i);}printf("%.6lf\n",ans); } int main() { #ifdef ivorysifreopen("f1.in","r",stdin); #endifSolve();return 0; }

轉載于:https://www.cnblogs.com/ivorysi/p/9070513.html

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