自适应辛普森,卡了一页的精度。。。

毒瘤。

/*@Date    : 2019-07-30 07:58:53@Author  : Adscn (adscn@qq.com)@Link    : https://www.cnblogs.com/LLCSBlog*/#include
    
     using namespace std;#define IL inline#define RG register#define gi getint()#define gc getchar()#define File(a) freopen(a".in","r",stdin);freopen(a".out","w",stdout)IL int getint(){    RG int xi=0;    RG char ch=gc;    bool f=0;    while(ch<'0'||ch>'9')ch=='-'?f=1:f,ch=gc;    while(ch>='0'&&ch<='9')xi=(xi<<1)+(xi<<3)+ch-48,ch=gc;    return f?-xi:xi;}template
     
      IL void pi(T k,char ch=0){    if(k<0)k=-k,putchar('-');    if(k>=10)pi(k/10,0);    putchar(k%10+'0');    if(ch)putchar(ch);}typedef long double db;const db eps = 1e-7;int n,m,w,T,V;struct line{    db x,y,len,k,L,R;}L[5010];inline int dcmp(db a){    if(fabs(a)<(long double)eps)return 0;    return a<0?-1:1;}struct inter{    db l,r;    bool operator <(const inter & b)const{        if(dcmp(l-b.l)==0)return dcmp(r-b.r)<0;        return dcmp(l-b.l)<0;    }}c[307];inline db f(db x){    db s=0;int p=0;    for(int i=1;i<=m;++i)        if(dcmp(L[i].L-x)<0&&dcmp(x-L[i].R)<0)        {            if(fabs(L[i].k)>eps)            {                db t1=(x-L[i].x)/L[i].k+L[i].y,                t2=(x-L[i].x-L[i].len)/L[i].k+L[i].y;                c[++p].l=max(L[i].y,min(t1,t2));                c[p].r=min(L[i].y+(L[i].R-L[i].L-L[i].len)/fabs(L[i].k),max(t1,t2));            }            else return T;        }    if(!p)return 0;    sort(c+1,c+p+1);    db l=c[1].l,r=c[1].r;    for (int i=2;i<=p;++i)        if (dcmp(c[i].l-r)>0)s+=r-l,l=c[i].l,r=c[i].r;        else r = max(c[i].r,r);    s += r-l;    return s;}inline db simpson(db l,db r){db mid=(l+r)/2;return (f(l)+4*f(mid)+f(r))*(r-l)/6;}db autosimpson(db l,db r,db sum){    db mid=(l+r)/2;    db lsum=simpson(l,mid),rsum=simpson(mid,r);    if(fabs(lsum+rsum-sum)
      
       w)    {        L[m].R=w;        check(w-len,y+(w-len-x)/v,len,-v,t-(w-len-x)/v);    }    else if(l<-eps)        {            L[m].L=0;            check(0,y-x/v,len,-v,t+x/v);        }}int main(void){    n=gi,w=gi,T=gi,V=gi;    for(int i=1;i<=n;++i)    {        int x=gi,l=gi,v=gi;        if(v&&(x||l!=w))check(x,0,l,v,T);        else L[++m].k=0,L[m].L=x,L[m].R=x+l;    }    printf("%.2Lf",fabs((T*w-autosimpson(0,w,simpson(0,w)))*V-0.0004));    return 0;}