1. 程式人生 > 其它 >[網路流24題]P4014 分配問題+ P4015 運輸問題

[網路流24題]P4014 分配問題+ P4015 運輸問題

費用流模板題(怎麼全是費用流啊?)
https://www.luogu.com.cn/problem/P4014
https://www.luogu.com.cn/problem/P4015

P4014
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <vector>
#define endl '\n'
#define IOS                  \
    ios::sync_with_stdio(0); \
    cin.tie(0);              \
    cout.tie(0);
#define P pair<int, int>
typedef long long ll;
using namespace std;

typedef long long ll;
const int maxn = 220;
const ll inf = 1e18;
int n, cnt_edge = 1, S, T;
int a1[maxn], a2[maxn], head[maxn];
ll dis[maxn];
bool vis[maxn];
struct edge {
    int to, nxt;
    ll flow, cost;
} e[(maxn * maxn) << 2];
inline void add(int u, int v, ll w, ll c) {
    e[++cnt_edge].nxt = head[u];
    head[u] = cnt_edge;
    e[cnt_edge].to = v;
    e[cnt_edge].flow = w;
    e[cnt_edge].cost = c;
}
inline void addflow(int u, int v, ll w, ll c) {
    add(u, v, w, c);
    add(v, u, 0, -c);
}
inline bool spfa(int on) {
    memset(vis, 0, sizeof(vis));
    if (on == 1)
        for (int i = 0; i <= T; i++) dis[i] = inf;
    else
        for (int i = 0; i <= T; i++) dis[i] = -inf;

    queue<int> q;
    q.push(S);
    dis[S] = 0;
    vis[S] = 1;
    while (!q.empty()) {
        int x = q.front();
        q.pop();
        vis[x] = 0;
        for (int i = head[x]; i; i = e[i].nxt) {
            int y = e[i].to;
            // cout << "->" << y << endl;
            if ((on == 1 && e[i].flow && dis[y] > dis[x] + e[i].cost) ||
                (on == -1 && e[i].flow && dis[y] < dis[x] + e[i].cost)) {
                dis[y] = dis[x] + e[i].cost;
                if (!vis[y]) q.push(y), vis[y] = 1;
            }
        }
    }
    if (on == 1)
        return dis[T] != inf;
    else
        return dis[T] != -inf;
}
ll dfs(int x, ll lim) {
    vis[x] = 1;
    if (x == T || lim <= 0) return lim;
    ll res = lim;
    for (int i = head[x]; i; i = e[i].nxt) {
        int y = e[i].to;
        if (dis[y] != dis[x] + e[i].cost || e[i].flow <= 0 || vis[y]) continue;
        ll tmp = dfs(y, min(res, e[i].flow));
        res -= tmp;
        e[i].flow -= tmp;
        e[i ^ 1].flow += tmp;
        if (res <= 0) break;
    }
    return lim - res;
}
inline ll Dinic(int on) {
    ll res = 0, cost = 0;
    while (spfa(on)) {
        ll flow = dfs(S, inf);
        res += flow, cost += flow * dis[T];
    }
    return cost;
}
int main() {
    cin >> n;
    S = n + n + 1, T = n + n + 2;

    for (int i = 1; i <= n; i++) {
        addflow(S, i, 1, 0);
        addflow(n + i, T, 1, 0);
    }

    for (int i = 1, c; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            cin >> c;
            addflow(i, j + n, inf, c);
        }
    }

    cout << Dinic(1)<<endl;
    for (int i = 0; i < cnt_edge; i+=2) {
        e[i].flow += e[i ^ 1].flow;
        e[i ^ 1].flow = 0;
    }
    cout << Dinic(-1)<<endl;
    return 0;
}
P4015
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <vector>
#define endl '\n'
#define IOS                  \
    ios::sync_with_stdio(0); \
    cin.tie(0);              \
    cout.tie(0);
#define P pair<int, int>
typedef long long ll;
using namespace std;

typedef long long ll;
const int maxn = 120;
const ll inf = 1e18;
int n1, n2, cnt_edge = 1, S, T;
int a1[maxn], a2[maxn], head[maxn];
ll dis[maxn];
bool vis[maxn];
struct edge {
    int to, nxt;
    ll flow, cost;
} e[(maxn * maxn) << 2];
inline void add(int u, int v, ll w, ll c) {
    e[++cnt_edge].nxt = head[u];
    head[u] = cnt_edge;
    e[cnt_edge].to = v;
    e[cnt_edge].flow = w;
    e[cnt_edge].cost = c;
}
inline void addflow(int u, int v, ll w, ll c) {
    add(u, v, w, c);
    add(v, u, 0, -c);
}
inline bool spfa(int on) {
    memset(vis, 0, sizeof(vis));
    if (on == 1)
        for (int i = 0; i <= T; i++) dis[i] = inf;
    else
        for (int i = 0; i <= T; i++) dis[i] = -inf;

    queue<int> q;
    q.push(S);
    dis[S] = 0;
    vis[S] = 1;
    while (!q.empty()) {
        int x = q.front();
        q.pop();
        vis[x] = 0;
        for (int i = head[x]; i; i = e[i].nxt) {
            int y = e[i].to;
            // cout << "->" << y << endl;
            if ((on == 1 && e[i].flow && dis[y] > dis[x] + e[i].cost) ||
                (on == -1 && e[i].flow && dis[y] < dis[x] + e[i].cost)) {
                dis[y] = dis[x] + e[i].cost;
                if (!vis[y]) q.push(y), vis[y] = 1;
            }
        }
    }
    if (on == 1)
        return dis[T] != inf;
    else
        return dis[T] != -inf;
}
ll dfs(int x, ll lim) {
    vis[x] = 1;
    if (x == T || lim <= 0) return lim;
    ll res = lim;
    for (int i = head[x]; i; i = e[i].nxt) {
        int y = e[i].to;
        if (dis[y] != dis[x] + e[i].cost || e[i].flow <= 0 || vis[y]) continue;
        ll tmp = dfs(y, min(res, e[i].flow));
        res -= tmp;
        e[i].flow -= tmp;
        e[i ^ 1].flow += tmp;
        if (res <= 0) break;
    }
    return lim - res;
}
inline ll Dinic(int on) {
    ll res = 0, cost = 0;
    while (spfa(on)) {
        ll flow = dfs(S, inf);
        res += flow, cost += flow * dis[T];
    }
    return cost;
}
int main() {
    cin >> n1 >> n2;
    S = n1 + n2 + 1, T = n1 + n2 + 2;

    for (int i = 1; i <= n1; i++) {
        cin >> a1[i];
        addflow(S, i, a1[i], 0);
    }

    for (int i = 1; i <= n2; i++) {
        cin >> a2[i];
        addflow(n1 + i, T, a2[i], 0);
    }

    for (int i = 1, c; i <= n1; i++) {
        for (int j = 1; j <= n2; j++) {
            cin >> c;
            addflow(i, j + n1, inf, c);
        }
    }

    cout << Dinic(1)<<endl;
    for (int i = 0; i < cnt_edge; i+=2) {
        e[i].flow += e[i ^ 1].flow;
        e[i ^ 1].flow = 0;
    }
    cout << Dinic(-1)<<endl;
    return 0;
}