"BZOJ1597" "Usaco2008 Mar" Land purchase slope optimization DP

The first step is to sequence the block, then remove the block contained by the other block, then the slope optimization dp

DP equation: f[i]=f[j]+a[i]*b[j+1];

Exactly what x ah y ah what in the code comment inside.

..... Tangled up dead. Start all kinds of WA and now discover:

Inline long long Xmul (point i,point j,point k) {(I.Y-J.Y) * (j.x-k.x)-(J.Y-K.Y) * (i.x-j.x);}

The code above can be compiled ... and unable to spit out the groove. Be sure to compile the file with the Terminal +wall command later.

Warning Day does not die, code day does not run!!!!

...... It's been a long, long time. Heartache Ah.

#include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #define N 50500# Define INF 0x3f3f3f3f/*f[j]=-a[i]*b[j+1]+f[i]y=f[j]x=b[j+1]k=-a[i] guarantee A does not drop, that is, K does not rise b=f[i] maintenance on the convex package */using namespace std; struct Point{long long x,y;int ID; Point (Long long _x,long long _y,int _id): X (_x), Y (_y), id (_id) {}point () {}}now,que[n];inline long long Xmul (Point I,point J , point K) {return (I.Y-J.Y) * (j.x-k.x)-(J.Y-K.Y) * (i.x-j.x);} int N,l,r;long long f[n];struct mrx{long long a,b;bool operator < (const MRX &c) const{if (A==C.A) return B<c.b;ret Urn a<c.a;}} Mrx[n];int Main () {//freopen ("test.in", "R", stdin),//freopen ("My.out", "w", stdout), int i,j,k;scanf ("%d", &n); for (i=1;i<=n;i++) scanf ("%d%d", &mrx[i].a,&mrx[i].b); sort (mrx+1,mrx+n+1); int Edl=0;long long maxx=0;for (i=n ; i;i--) {if (Mrx[i].b<=maxx) Edl++,mrx[i].a=mrx[i].b=inf;else maxx=mrx[i].b;} Sort (mrx+1,mrx+n+1); N-=edl;memset (F,0x3f,sizeof (f)); F[0]=0;que[0].x=mrx[1].b;for (i=1;i<=n;i++) {int K=-mrx[i] . A;//while (L< r&&que[l].y-que[l+1].y>= (que[l].x-que[l+1].x) *k) l++; Slope version while (l<r&&f[que[l].id]+mrx[i].a*mrx[que[l].id+1].b>=f[que[l+1].id]+mrx[i].a*mrx[que[l+1]. ID+1].B) l++; Function value version now=point (mrx[i+1].b,f[i]=f[que[l].id]+mrx[i].a*mrx[que[l].id+1].b,i); while (L<r&&xmul (now,que [r],que[r-1]) >=0) r--;//while (l<r&& (NOW.Y-QUE[R].Y) * (que[r].x-que[r-1].x) >= (Que[r].y-que[r-1]. Y) * (now.x-que[r].x))--r;que[++r]=now;} Cout<<f[n]<<endl;return 0;}

。。。。。

"BZOJ1597" "Usaco2008 Mar" Land purchase slope optimization DP