bzoj1061: [Noi2008] Volunteer recruitment

Orz

The https://www.byvoid.com/blog/noi-2008-employee/here.

Only for the time being understood

Since inequality cannot be poor, plus Yi becomes equation

After the difference, each x appears at most once, so that you can consider the impact of two (through the edge, where the outflow so much there will flow in so, corresponding to a positive and negative)

1#include <cstdio>2#include <cstring>3#include <cstdlib>4#include <algorithm>5#include <iostream>6 7 using namespacestd;8 9 voidSetio (Const string&s) {TenFreopen ((S +". in"). C_STR (),"R", stdin); OneFreopen ((S +". out"). C_STR (),"W", stdout); A } -Template<typename q> Q Read (q&x) { -     Static Charc, F; the      for(f =0; c = GetChar (),!isdigit (c); )if(c = ='-') F =1; -      for(x =0; IsDigit (c); c = GetChar ()) x = x *Ten+ C-'0'; -     if(f) x =-x; -     returnx; + } -Template<typename q>Q Read () { +     StaticQ x; Read (x);returnx; A } at //MCMF -  - Const intN = ++Ten, M =25000+Ten, INF = ~0u>>1; -  - structEdge { -     intto, ADV, cost; inEdge *Next; -Edge (intto =0,intadv =0,intCost =0, Edge *next =0): To, ADV (ADV), cost, next (next) {} to}pool[m *2], *pis = Pool, *Fir[n]; +  - voidAddedge (intUintVintWintc) { theFir[u] =New(pis++) Edge (V, W, C, Fir[u]); *FIR[V] =New(pis++) Edge (U,0, -c, Fir[v]); $ }Panax Notoginseng  - #defineINV (p) (Pool + (((p)-pool) ^1) the  + namespaceMCMF { A     intN, S, T; the     intD[n], q[n], QL, QR, a[n]; +Edge *Pre[n]; -     BOOLInq[n]; $      $     BOOLInsertintUintDisint( ) { -         if(D[u] >dis) { -A[u] =; theD[u] =dis; -             if(!Inq[u]) {Wuyiq[qr++] =u; the                 if(QR = = N) QR =0; -Inq[u] =1; Wu             } -             return 1; About}return 0; $     } -      -     BOOLSPFA (int& Flow,int&Cost ) { -          for(intU =1; U <= N; u++) D[u] = INF, inq[u] =0; AInsert (S,0, INF); +          while(QL ^qr) { the             intU = q[ql++];if(QL = = N) QL =0; Inq[u] =0; -              for(Edge *p = fir[u]; p; p = p->next)if(p->adv) { $                 if(Insert (P->to, D[u] + p->cost, min (A[u], p->adv)))  { thePre[p->to] =p; the                 } the             } the         } -         if(D[t] = = INF)return 0; inFlow + =A[t]; theCost + = d[t] *A[t]; the          for(intu = t; U! = S; U = INV (Pre[u])To ) { AboutPRE[U]-&GT;ADV-=A[t]; theINV (Pre[u])->adv + =A[t]; the         } the         return 1; +     } -      the     intMainint_n,int_s,int_t) {Bayin = _n, s = _s, t =_t; the         intFlow =0, cost =0; the          while(SPFA (flow, cost)); -         returnCost ; -     } the } the  the Const intMAXN = ++Ten, MAXM =10000+Ten; the intDEMAND[MAXN]; -  the intMain () { the #ifdef DEBUG theFreopen ("In.txt","R", stdin);94Freopen ("OUT.txt","W", stdout); the #endif the      the     intn = read<int> (), M = read<int>();98     ints = n +2, T = s +1; About      for(inti =1; I <= N; i++) { - read (demand[i]);101Addedge (i +1, I, INF,0);102     }103      for(inti =1; I <= n +1; i++) {104         intDLT = Demand[i]-demand[i-1]; the         if(DLT >=0) Addedge (S, I, DLT,0);106         ElseAddedge (i, T,-DLT,0);107     }108     intL, R, C;109      for(inti =1; I <= m; i++) { the Read (l), read ( R), read (c);111Addedge (L, R +1, INF, c); the     }113      theprintf"%d\n", Mcmf::main (t, S, t)); the      the     return 0;117}

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bzoj1061: [Noi2008] Volunteer recruitment