BZOJ1027 [JSOI2007] Alloy

Each item has three parameters, actually equivalent to two, because the sum is determined.
Then the problem becomes a pile of points on the two-dimensional plane, and the convex hull of the smallest subset of B is formed, including these points a.
Use a Floyd around a circle.

1 /**************************************************************2 problem:10273 User:rausen4 language:c++5 result:accepted6 time:1136 Ms7 memory:1820 KB8 ****************************************************************/9  Ten#include <cstdio> One#include <cmath> A#include <algorithm> -   - #defineP Point the using namespacestd; -typedefDoubleLF; - Const intN =505; - Const intINF =1e9; + ConstLF EPS = 1e-8; -   + structPoint { A lf x, y; at P () {} - P (LF _x, LF _y): X (_x), Y (_y) {} -       -InlineBOOL operator!= (ConstP p)Const { -         returnFabs (x-p.x) > EPS | | Fabs (Y-P.Y) >EPS; -     } inInline Poperator-(P p) { -         returnP (x-p.x, Y-p.y); to     } +Inline LFoperator*(P p) { -         returnX * p.y-y *p.x; the     } *       $InlinevoidRead () {Panax Notoginsengscanf"%LF%LF%*LF", &x, &y); -     } the } A[n], b[n]; +   A intN, M; the intDis[n][n]; +   - BOOLIn_one_line (P x, p y) { $     inti; $     if(x.x >y.x) Swap (x, y); -      for(i =1; I <= m; ++i) -         if(b[i].x < x.x | | b[i].x > y.x)return 0; the     if(X.y >y.y) Swap (x, y); -      for(i =1; I <= m; ++i)Wuyi         if(B[i].y < x.y | | b[i].y > Y.Y)return 0; the     return 1; - } Wu   - intCheck (P x, p y) { About     intI, Cnt1, Cnt2; $ LF tmp; -      for(i =1, cnt1 = Cnt2 =0; I <= m; ++i) { -TMP = (y-x) * (B[i]-x); -         if(tmp > EPS) + +cnt1; A         if(TMP <-EPS) + +Cnt2; +         if(Cnt1 && Cnt2)return 0; the     } -     if(!cnt1 &&!cnt2 &&in_one_line (x, y)) { $Puts"2"); the         return-1; the     } the     returnCnt1?1: Cnt2?2:3; the } -   in voidFloyd () { the     intAns =inf, I, J, K; the      for(k =1; K <= N; ++k) About          for(i =1; I <= N; ++i) the              for(j =1; J <= N; ++j) theDis[i][j] = min (Dis[i][j], dis[i][k] +dis[k][j]); the      for(i =1; I <= N; ++i) +Ans =min (ans, dis[i][i]); -     if(ans = = inf | | ans <=2) puts ("-1"); the     Elseprintf"%d\n", ans);Bayi } the   the voidsolve () { -     intI, J, F; -      for(i =1; I <= N; ++i) the          for(j =1; J <= N; ++j) theDIS[I][J] =inf; the      for(i =1; I <= N; ++i) the          for(j = i +1; J <= N; ++j) { -f =Check (A[i], a[j]); the             if(f = =-1)return; the             if(f = =1) Dis[i][j] =1; the             Else if(f = =2) Dis[j][i] =1;94             Else if(f = =3) Dis[i][j] = dis[j][i] =1; the         } the Floyd (); the }98   About BOOLSpecial_judge () { -     inti;101      for(i =1; I <= N; ++i)102         if(a[1]! = A[i])return 0;103      for(i =1; I <= m; ++i)104         if(a[1]! = B[i])return 0; thePuts"1");106     return 1;107 }108  109 intMain () { the     inti;111scanf"%d%d", &n, &m); the      for(i =1; I <= N; ++i)113 A[i].read (); the      for(i =1; I <= m; ++i) the B[i].read (); the     if(Special_judge ())return 0;117 solve ();118     return 0;119}

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BZOJ1027 [JSOI2007] Alloy