【网络流】 csu 1623 Inspectors

#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 205
#define maxm 500005
#define eps 1e-12
#define mod 998244353
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
//#define ls o<<1
//#define rs o<<1 | 1
//#define lson o<<1, L, mid
//#define rson o<<1 | 1, mid+1, R
//#pragma comment(linker, "/STACK:102400000,102400000")
#define pii pair<int, int>
typedef long long LL;
typedef unsigned long long ULL;
//typedef int LL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
// head

struct Edge
{
int v, c, w, next;
Edge(int v = 0, int c = 0, int w = 0, int next = 0) : v(v), c(c), w(w), next(next) {}
}E[maxm];

queue<int> q;
int H[maxn], cntE;
int vis[maxn];
int cap[maxn];
int dis[maxn];
int cur[maxn];
int n, m, flow, cost, s, t, T;

void addedges(int u, int v, int c, int w)
{
E[cntE] = Edge(v, c, w, H[u]);
H[u] = cntE++;
E[cntE] = Edge(u, 0, -w, H[v]);
H[v] = cntE++;
}

bool spfa()
{
memset(dis, INF, sizeof dis);
cur[s] = -1;
vis[s] = ++T;
dis[s] = 0;
cap[s] = INF;
q.push(s);
while(!q.empty()) {
int u = q.front();
q.pop();
vis[u] = T - 1;
for(int e = H[u]; ~e; e = E[e].next) {
int v = E[e].v, c = E[e].c, w = E[e].w;
if(c && dis[u] + w < dis[v]) {
dis[v] = dis[u] + w;
cap[v] = min(cap[u], c);
cur[v] = e;
if(vis[v] != T) {
vis[v] = T;
q.push(v);
}
}
}
}
if(dis[t] == INF) return false;
flow += cap[t];
cost += cap[t] * dis[t];
for(int e = cur[t]; ~e; e = cur[E[e ^ 1].v]) {
E[e].c -= cap[t];
E[e ^ 1].c += cap[t];
}
return true;

}

int mcmf()
{
flow = cost = 0;
while(spfa());
return cost;
}

void init()
{
cntE = T = 0;
memset(H, -1, sizeof H);
memset(vis, 0, sizeof vis);
}

void work(int _)
{
init();
scanf("%d", &n);
int w;
s = 0, t = 2 * n + 1;
for(int i = 1; i < n; i++)
for(int j = i+1; j <= n; j++) {
scanf("%d", &w);
addedges(i, j+n, 1, w);
addedges(j, i+n, 1, w);
}
for(int i = 1; i <= n; i++) addedges(s, i, 1, 0);
for(int i = 1; i <= n; i++) addedges(i+n, t, 1, 0);
printf("Case %d: %d\n", _, mcmf());
}

int main()
{
int _;
scanf("%d", &_);
for(int i = 1; i <= _; i++) work(i);

return 0;
}