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| #include <iostream>
#include <cstdio>
#include <queue>
#include <climits>
#include <algorithm>
#define inf INT_MAX
using namespace std;
const int N = 510, M = 2e5 + 10;
int n, m, st, ed, k, matrix_idx, d[N], cur[N];
int idx, hd[N], nxt[M], edg[M], wt[M];
struct Edge
{
int u, v, w;
void add(int a, int b, int c)
{
u = a;
v = b;
w = c;
}
}matrix[M];
bool bfs()
{
for (int i = st; i <= ed; i++)
d[i] = -1;
d[st] = 0;
cur[st] = hd[st];
queue <int> q;
q.push(st);
while (!q.empty())
{
int t = q.front();
q.pop();
for (int i = hd[t]; ~i; i = nxt[i])
if (d[edg[i]] == -1 && wt[i])
{
cur[edg[i]] = hd[edg[i]];
d[edg[i]] = d[t] + 1;
if (edg[i] == ed)
return true;
q.push(edg[i]);
}
}
return false;
}
int exploit(int x, int limit)
{
if (x == ed)
return limit;
int res = 0;
for (int i = cur[x]; ~i && res < limit; i = nxt[i])
{
cur[x] = i;
if (d[edg[i]] == d[x] + 1 && wt[i])
{
int t = exploit(edg[i], min(wt[i], limit - res));
if (!t)
d[edg[i]] = -1;
wt[i] -= t;
wt[i ^ 1] += t;
res += t;
}
}
return res;
}
int dinic()
{
int res = 0, flow;
while (bfs())
while (flow = exploit(st, inf))
res += flow;
return res;
}
void add(int a, int b, int c)
{
nxt[++idx] = hd[a];
hd[a] = idx;
edg[idx] = b;
wt[idx] = c;
}
bool check(int x)
{
idx = -1;
for (int i = st; i <= ed; i++)
hd[i] = -1;
for (int i = 1; i <= n; i++)
{
add(st, i, 1);
add(i, st, 0);
}
for (int i = 1; i <= matrix_idx; i++)
if (matrix[i].w <= x)
{
add(matrix[i].u, matrix[i].v, 1);
add(matrix[i].v, matrix[i].u, 0);
}
else
break;
for (int i = n + 1; i < ed; i++)
{
add(i, ed, 1);
add(ed, i, 0);
}
return dinic() >= n - k + 1;
}
bool cmp(Edge x, Edge y)
{
return x.w < y.w;
}
int main()
{
int l = inf, r = 0, mid;
cin >> n >> m >> k;
st = 0;
ed = n + m + 1;
for (int i = 1, a; i <= n; i++)
for (int j = 1; j <= m; j++)
{
cin >> a;
matrix[++matrix_idx].add(i, j + n, a);
l = min(l, a);
r = max(r, a);
}
sort(matrix + 1, matrix + matrix_idx + 1, cmp);
while (l < r)
{
mid = l + r >> 1;
if (check(mid))
r = mid;
else
l = mid + 1;
}
cout << l;
return 0;
}
|