"bzoj4443" [Scoi2015] small convex play matrix

The K-Large is n-k+1 small, so you can answer the two points (Jianggo said a similar question)

The two-point answer finds the coordinates of the position of the number that is smaller than the current answer, determines whether the n-k+1 number that satisfies the same column in the same row can be selected, and then runs Hungary, and for a coordinate (x, y) if the current answer to A[x][y]≤a[x][y is met, the line x is connected to the Y column, Then run Hungary to determine if the maximum match is greater than n-k+1

#include<algorithm> #include<iostream> #include<cstdlib> #include<cstring> #include<cstdio> #include<cmath> #include<queue> #include<set> using namespace std; #define M 300 #define N 1000001 struct edge {      int v,next; }e[N<<1]; int head[N<<1]; int cnt; int map[M][M]; int ly[N],f[N]; int n,m,k; int l,r; int maxn,tot,ans; void link( int x, int y) {      e[++cnt]=(edge){y,head[x]};      head[x]=cnt; } bool find( int d) {      for ( int i=head[d];i;i=e[i].next)      {          int t=e[i].v;          if (ly[t]!=tot)          {              ly[t]=tot;              if (!f[t] || find(f[t]))              {                  f[t]=d;                  return true ;              }          }      }      return false ; } int work( int x) {      ans=cnt=0;      memset (head,0, sizeof (head));      memset (f,0, sizeof (f));      for ( int i=1;i<=n;i++)          for ( int j=1;j<=m;j++)              if (map[i][j]<=x)                  link(i,j);      for ( int i=1;i<=n;i++)      {          tot++;          ans+=find(i);      }      return ans>=k ? 1: 0; } int main() {      scanf ( "%d%d%d" ,&n,&m,&k);      k=n-k+1;      for ( int i=1;i<=n;i++)          for ( int j=1;j<=m;j++)              scanf ( "%d" ,&map[i][j]),maxn=max(maxn,map[i][j]);      l=1;      r=maxn;      while (l<r)      {          int m=l+r>>1;          if (work(m))              r=m;          else              l=m+1;      }      printf ( "%d\n" ,l);      return 0; }

"bzoj4443" [Scoi2015] small convex play matrix