思路:
将问题转化成最小费用流
代码:
#pragma GCC optimize(2) #pragma GCC optimize(3) #pragma GCC optimize(4) #include<bits/stdc++.h> using namespace std; #define y1 y11 #define fi first #define se second #define pi acos(-1.0) #define LL long long //#define mp make_pair #define pb push_back #define ls rt<<1, l, m #define rs rt<<1|1, m+1, r #define ULL unsigned LL #define pll pair<LL, LL> #define pli pair<LL, int> #define pii pair<int, int> #define piii pair<pii, int> #define pdd pair<double, double> #define mem(a, b) memset(a, b, sizeof(a)) #define debug(x) cerr << #x << " = " << x << " "; #define fio ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); //head const int N = 200 + 10; const int INF = 0x3f3f3f3f; int a[N][N]; struct edge { int to, cap, cost, rev; }; int V; vector<edge>g[N]; int h[N], dis[N], prevv[N], preve[N]; void add_edge(int u, int v, int cap, int cost) { g[u].pb({v, cap, cost, g[v].size()}); g[v].pb({u, 0, -cost, g[u].size()-1}); } int min_cost_flow(int s, int t, int f) { int res = 0; mem(h, 0); while(f > 0) { priority_queue<pii, vector<pii>, greater<pii> > q; mem(dis, 0x3f); dis[s] = 0; q.push({0, s}); while(!q.empty()) { pii p = q.top(); q.pop(); int v = p.se; if(dis[v] < p.fi) continue; for (int i = 0; i < g[v].size(); ++i) { edge &e = g[v][i]; if(e.cap > 0 && dis[e.to] > dis[v] + e.cost + h[v] - h[e.to]) { dis[e.to] = dis[v] + e.cost + h[v] - h[e.to]; prevv[e.to] = v; preve[e.to] = i; q.push({dis[e.to], e.to}); } } } if(dis[t] == INF) return -1; for (int v = 0; v < V; ++v) h[v] += dis[v]; int d = f; for (int v = t; v != s; v = prevv[v]) d = min(d, g[prevv[v]][preve[v]].cap); f -= d; res += d*h[t]; for (int v = t; v != s; v = prevv[v]) { edge &e = g[prevv[v]][preve[v]]; e.cap -= d; g[v][e.rev].cap += d; } } return res; } int main() { int n = 15; for (int i = 1; i <= n; ++i) { for (int j = 1; j <= n; ++j) { scanf("%d", &a[i][j]); add_edge(i, j+n, 1, 1000-a[i][j]); } } int s = 0, t = n+n+1; V = t+1; for (int i = 1; i <= n; ++i) add_edge(s, i, 1, 0); for (int i = 1; i <= n; ++i) add_edge(i+n, t, 1, 0); cout << 1000*n - min_cost_flow(s, t, n); return 0; }