[BeiJing wc2012]连连看

题目链接 费用流板子+拆点

 #include <bits/stdc++.h>
 using namespace std;
 typedef long long ll;
 inline int read()
 {
     int x=,f=;char ch=getchar();
     while(ch<''||ch>''){if(ch=='-')f=-;ch=getchar();}
     while(ch>=''&&ch<=''){x=x*+ch-'';ch=getchar();}
     return x*f;
 }

 /********************************************************************/

 struct ZKM_MinCostMaxFlow{
     const static int maxn = 1e5+;
     const static int maxE = 1e5+;
     const static int INF = 0xfffffff;

     struct Edge{
         int to, next, cap, flow, cost;
         Edge(int _to = , int _next = , int _cap = , int _flow = , int _cost = ):
             to(_to), next(_next), cap(_cap), flow(_flow), cost(_cost){}
     }edge[maxE*];

     int head[maxn], tot;
     int cur[maxn], dis[maxn];
     bool vis[maxn];
     int ss, tt, N;
     int min_cost, max_flow;
     void init(int N){
         tot = ;
         for(int i = ;i < N;i++) head[i] = -;
     }
     int addedge(int u, int v, int cap, int cost){
         edge[tot] = Edge(v, head[u], cap, , cost);
         int rs = tot;
         head[u] = tot++;
         edge[tot] = Edge(u, head[v], , , -cost);
         head[v] = tot++;
         return rs;
     }
     int aug(int u, int flow){
         if(u == tt) return flow;
         vis[u] = true;
         for(int i = cur[u];i != -;i = edge[i].next){
             int v = edge[i].to;
             if(edge[i].cap > edge[i].flow && !vis[v] && dis[u] == dis[v] + edge[i].cost){
                 int tmp = aug(v, min(flow, edge[i].cap - edge[i].flow));
                 edge[i].flow += tmp;
                 edge[i^].flow -= tmp;
                 cur[u] = i;
                 if(tmp) return tmp;
             }
         }
         return ;
     }
     bool modify_label(){
         int d = INF;
         for(int u = ;u < N;u++){
             if(vis[u]){
                 for(int i = head[u];i != -;i = edge[i].next){
                     int v = edge[i].to;
                     if(edge[i].cap > edge[i].flow && !vis[v]){
                         d = min(d, dis[v]+edge[i].cost - dis[u]);
                     }
                 }
             }
         }
         if(d == INF) return false;
         for(int i = ;i < N;i++){
             if(vis[i]){
                 vis[i] = false;
                 dis[i] += d;
             }
         }
         return true;
     }

     pair<int, int> mincostmaxflow(int start, int ed, int n){
         ss = start, tt = ed, N = n;
         min_cost = max_flow = ;
         for(int i = ;i < n;i++) dis[i] = ;
         while(){
             for(int i = ;i < n;i++) cur[i] = head[i];
             while(){
                 for(int i = ;i < n;i++) vis[i] = false;
                 int tmp = aug(ss, INF);
                 if(tmp == ) break;
                 max_flow += tmp;
                 min_cost += tmp*dis[ss];
             }
             if(!modify_label()) break;
         }
         return make_pair( max_flow, min_cost );
     }
 }solver;

 int gcd(int x, int y){
     if(y == ) return x;
     else return gcd(y, x%y);
 }

 bool check(int x, int y){
     if(x == y) return false;
     if(x < y)  swap(x, y);
     int t = sqrt(x*x-y*y);
     if(t*t != x*x-y*y) return false;
     if(gcd(y, t) != ) return false;
     return true;
 }

 int main(){
     int a, b;
     a = read(); b = read();
     solver.init(b*+);
     for(int i = a;i <= b;i++){
         for(int j = a;j <= b;j++){
             if(check(i, j)){
                 solver.addedge(i, j+b, , -i-j);
             }
         }
         solver.addedge(b*+, i, , );     //拆点
         solver.addedge(i+b, b*+, , );   //拆点
     }
     pair<int, int> ans = solver.mincostmaxflow(b*+, b*+, b*+);
     printf("%d %d\n", ans.first/, -ans.second/);
     return ;
 }