/* 题意:k个挤奶机,每天可以给m头奶牛挤奶,让奶牛到达挤奶机的最大距离最小 题解:很明朗的二分答案的题目,不解释 先floyd求任意点之间的最短路,然后二分答案建图判断是否满足要求 */ #include <cstdio> #include <iostream> #include<queue> #include<set> #include<ctime> #include<algorithm> #include<cmath> #include<vector> #include<map> #include<cstring> using namespace std; const int inf=1<<30; const int maxn=1009; int dis[maxn][maxn]; struct edge { int v, next; int val; } net[ 500100 ]; int k,c,m; int level[maxn], Qu[maxn], out[maxn],next[maxn]; class Dinic { public: int end; Dinic() { end = 0; memset( next, -1, sizeof(next) ); } inline void insert( int x, int y, int c) { net[end].v = y, net[end].val = c, net[end].next = next[x], next[x] = end ++; net[end].v = x, net[end].val = 0, net[end].next = next[y], next[y] = end ++; } bool BFS( int S, int E ) { memset( level, -1, sizeof(level) ); int low = 0, high = 1; Qu[0] = S, level[S] = 0; for( ; low < high; ) { int x = Qu[low]; for( int i = next[x]; i != -1; i = net[i].next ) { if( net[i].val == 0 ) continue; int y = net[i].v; if( level[y] == -1 ) { level[y] = level[x] + 1; Qu[ high ++] = y; } } low ++; } return level[E] != -1; } int MaxFlow( int S, int E ){ int maxflow = 0; for( ; BFS(S, E) ; ) { memcpy( out, next, sizeof(out) ); int now = -1; for( ;; ) { if( now < 0 ) { int cur = out[S]; for(; cur != -1 ; cur = net[cur].next ) if( net[cur].val && out[net[cur].v] != -1 && level[net[cur].v] == 1 ) break; if( cur >= 0 ) Qu[ ++now ] = cur, out[S] = net[cur].next; else break; } int u = net[ Qu[now] ].v; if( u == E ) { int flow = inf; int index = -1; for( int i = 0; i <= now; i ++ ) { if( flow > net[ Qu[i] ].val ) flow = net[ Qu[i] ].val, index = i; } maxflow += flow; for( int i = 0; i <= now; i ++ ) net[Qu[i]].val -= flow, net[Qu[i]^1].val += flow; for( int i = 0; i <= now; i ++ ) { if( net[ Qu[i] ].val == 0 ) { now = index - 1; break; } } } else{ int cur = out[u]; for(; cur != -1; cur = net[cur].next ) if (net[cur].val && out[net[cur].v] != -1 && level[u] + 1 == level[net[cur].v]) break; if( cur != -1 ) Qu[++ now] = cur, out[u] = net[cur].next; else out[u] = -1, now --; } } } return maxflow; } }; void floyd() { for(int g=1;g<=k+c;g++) { for(int i=1;i<=k+c;i++)if(g!=i&&dis[i][g]!=-1) { for(int j=1;j<=k+c;j++)if(g!=j&&dis[g][j]!=-1) { if(dis[i][j]==-1||dis[i][j]>dis[i][g]+dis[g][j]) dis[i][j]=dis[i][g]+dis[g][j]; } } } } void build(int lim,Dinic &my) { for(int i=1;i<=k;i++) my.insert(0,i,m); for(int i=1;i<=k;i++) { for(int j=k+1;j<=k+c;j++) if(dis[i][j]<=lim&&dis[i][j]!=-1) { my.insert(i,j,1); } } for(int j=k+1;j<=k+c;j++) my.insert(j,k+c+1,1); } void solve() { int low=0,hei=20000,mid; while(low<hei-1) { mid=(low+hei)/2; Dinic my; build(mid,my); if(my.MaxFlow(0,k+c+1)==c) hei=mid; else low=mid; } printf("%d\n",hei); } int main() { while(scanf("%d%d%d",&k,&c,&m)!=EOF) { for(int i=1;i<=k+c;i++) for(int j=1;j<=k+c;j++) { scanf("%d",&dis[i][j]); if(i!=j&&dis[i][j]==0) dis[i][j]=-1; } floyd(); solve(); } }