POJ - 3436 ACM Computer Factory (ISAP EK Dinic)

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题目大意:有N台机器,每台机器能处理相应型态的电脑,处理完后,电脑将变成另一种形态。
每台机器有相应的工作限度,每次至多处理K台
现在问,在一次流水线生产中,最多可以产生多少台完整的电脑(流水线指的是在每一台机器的工作限度下)

解题思路:题目比较难理解,理解题目的话,就比较好做了
首先,将每台机器的点拆成两个点,权值为工作限度
如果机器能处理的电脑的状态全是0的话,就将其和超级源点连接,表示该机器进行第一步加工
如果机器处理完后的形态与另一台机器能处理的最初形态相同,就将其连线,表示下一台机器可以将其处理完的电脑再进一步加工
如果机器处理完后形态都为1,表示完工,将其和超级汇点相连,接着跑最大流

ISAP

#include <cstdio>#include <cstring>#include <algorithm>#include <vector>#include <queue>using namespace std;#define N 1010#define INF 0x3f3f3f3fstruct Edge {    int from, to, cap, flow;    Edge() {}    Edge(int from, int to, int cap, int flow): from(from), to(to), cap(cap), flow(flow) {}};int g[70][70];struct ISAP {    int p[N], num[N], cur[N], d[N];    int t, s, n, m;    bool vis[N];    vector<int> G[N];    vector<Edge> edges;    void init(int n) {        this->n = n;        for (int i = 0; i <= n; i++) {            G[i].clear();            d[i] = INF;        }        edges.clear();    }    void AddEdge(int from, int to, int cap) {        edges.push_back(Edge(from, to, cap, 0));        edges.push_back(Edge(to, from, 0, 0));        int m = edges.size();        G[from].push_back(m - 2);        G[to].push_back(m - 1);    }    bool BFS() {        memset(vis, 0, sizeof(vis));        queue<int> Q;        d[t] = 0;        vis[t] = 1;        Q.push(t);        while (!Q.empty()) {            int u = Q.front();            Q.pop();            for (int i = 0; i < G[u].size(); i++) {                Edge &e = edges[G[u][i] ^ 1];                if (!vis[e.from] && e.cap > e.flow) {                    vis[e.from] = true;                    d[e.from] = d[u] + 1;                    Q.push(e.from);                }            }        }        return vis[s];    }    int Augment() {        int u = t, flow = INF;        while (u != s) {            Edge &e = edges[p[u]];            flow = min(flow, e.cap - e.flow);            u = edges[p[u]].from;        }        u = t;        while (u != s) {            edges[p[u]].flow += flow;            edges[p[u] ^ 1].flow -= flow;            u = edges[p[u]].from;        }        return flow;    }    int Maxflow(int s, int t) {        this->s = s; this->t = t;        int flow = 0;        BFS();        if (d[s] >= n)            return 0;        memset(num, 0, sizeof(num));        memset(cur, 0, sizeof(cur));        for (int i = 0; i < n; i++)            if (d[i] < INF)                num[d[i]]++;        int u = s;        while (d[s] < n) {            if (u == t) {                flow += Augment();                u = s;            }            bool ok = false;            for (int i = cur[u]; i < G[u].size(); i++) {                Edge &e = edges[G[u][i]];                if (e.cap > e.flow && d[u] == d[e.to] + 1) {                    ok = true;                    p[e.to] = G[u][i];                     cur[u] = i;                    u = e.to;                    break;                }            }            if (!ok) {                int Min = n - 1 ;                for (int i = 0; i < G[u].size(); i++) {                    Edge &e = edges[G[u][i]];                    if (e.cap > e.flow)                        Min = min(Min, d[e.to]);                }                if (--num[d[u]] == 0)                    break;                num[d[u] = Min + 1]++;                cur[u] = 0;                if (u != s)                    u = edges[p[u]].from;            }        }        return flow;    }};ISAP isap;#define M 70#define P 20int in[M][P], out[M][P], f[M];int n, m;bool NullJudge(int cur) {    for (int i = 1; i <= n; i++)        if (in[cur][i] == 1)            return false;    return true;}bool FullJudge(int cur) {    for (int i = 1; i <= n; i++)        if (!out[cur][i])            return false;    return true;}bool connect(int x, int y) {    for (int i = 1; i <= n; i++)        if (out[x][i] + in[y][i] == 1)            return false;    return true;}void init() {    for (int i = 1; i <= m; i++) {        scanf("%d", &f[i]);        for (int j = 1; j <= n; j++)            scanf("%d", &in[i][j]);        for (int j = 1; j <= n; j++)            scanf("%d", &out[i][j]);    }    int s = 2 * m + 1;    int t = 2 * m + 2;    isap.init(t);    for (int i = 1; i <= m; i++) {        isap.AddEdge(i, i + m, f[i]);        if (NullJudge(i))            isap.AddEdge(s, i, f[i]);        if (FullJudge(i))            isap.AddEdge(i + m, t, f[i]);        for (int j = 1; j <= m; j++)             if (i != j && connect(i, j))                isap.AddEdge(i + m, j, f[i]);    }    int ans[M][P];    int flow = isap.Maxflow(s, t);    int cnt = 0;    for (int i = m + 1; i <= m + m; i++)        for (int j = 0; j < isap.G[i].size(); j++) {            int v = isap.G[i][j];            Edge &e = isap.edges[v];            if (e.flow > 0 && e.to <= m) {                ans[cnt][0] = i - m;                ans[cnt][1] = e.to;                ans[cnt][2] = e.flow;                cnt++;            }        }    printf("%d %d\n", flow, cnt);    for (int i = 0; i < cnt; i++)        printf("%d %d %d\n", ans[i][0], ans[i][1], ans[i][2]);}int main() {    while (scanf("%d%d", &n, &m) == 2) {        init();    }    return 0;}

EK

#include <cstdio>#include <cstring>#include <queue>#include <algorithm>#include <vector>using namespace std;#define N 1010#define INF 0x3f3f3f3fstruct Edge{    int from, to, cap, flow;    Edge() {}    Edge(int from, int to, int cap, int flow): from(from), to(to), cap(cap), flow(flow){}};struct EK{    vector<int> G[N];    vector<Edge> edges;    int s, t, n, m, p[N];    bool vis[N];    void init(int n) {        this->n = n;        for (int i = 0; i <= n; i++)            G[i].clear();        edges.clear();    }    void AddEdge(int from, int to, int cap) {        edges.push_back(Edge(from, to, cap, 0));        edges.push_back(Edge(to, from, 0, 0));        m = edges.size();        G[from].push_back(m - 2);        G[to].push_back(m - 1);    }    bool BFS() {        queue<int> q;        memset(vis, 0, sizeof(vis));        vis[s] = 1;        q.push(s);        while (!q.empty()) {            int u = q.front();            q.pop();            for (int i = 0; i < G[u].size(); i++) {                Edge &e = edges[G[u][i]];                if (!vis[e.to] && e.cap > e.flow) {                    vis[e.to] = true;                    p[e.to] = G[u][i];                    if (e.to == t)                        return true;                    q.push(e.to);                }            }        }        return false;    }    int Augment() {        int flow = INF, u = t;        while (u != s) {            Edge &e = edges[p[u]];            flow = min(flow, e.cap - e.flow);            u = e.from;        }        u = t;        while (u != s) {            edges[p[u]].flow += flow;            edges[p[u] ^ 1].flow -= flow;            u = edges[p[u]].from;        }        return flow;    }    int Maxflow(int s, int t) {        this->s = s; this->t = t;        int flow = 0;        while (BFS()) {            flow += Augment();        }        return flow;    }};EK ek;#define M 70#define P 20int in[M][P], out[M][P], f[M];int n, m;bool NullJudge(int cur) {    for (int i = 1; i <= n; i++)        if (in[cur][i] == 1)            return false;    return true;}bool FullJudge(int cur) {    for (int i = 1; i <= n; i++)        if (!out[cur][i])            return false;    return true;}bool connect(int x, int y) {    for (int i = 1; i <= n; i++)        if (out[x][i] + in[y][i] == 1)            return false;    return true;}void init() {    for (int i = 1; i <= m; i++) {        scanf("%d", &f[i]);        for (int j = 1; j <= n; j++)            scanf("%d", &in[i][j]);        for (int j = 1; j <= n; j++)            scanf("%d", &out[i][j]);    }    int s = 2 * m + 1;    int t = 2 * m + 2;    ek.init(t);    for (int i = 1; i <= m; i++) {        ek.AddEdge(i, i + m, f[i]);        if (NullJudge(i))            ek.AddEdge(s, i, f[i]);        if (FullJudge(i))            ek.AddEdge(i + m, t, f[i]);        for (int j = 1; j <= m; j++)             if (i != j && connect(i, j))                ek.AddEdge(i + m, j, f[i]);    }    int ans[M][P];    int flow = ek.Maxflow(s, t);    int cnt = 0;    for (int i = m + 1; i <= m + m; i++)        for (int j = 0; j < ek.G[i].size(); j++) {            int v = ek.G[i][j];            Edge &e = ek.edges[v];            if (e.flow > 0 && e.to <= m) {                ans[cnt][0] = i - m;                ans[cnt][1] = e.to;                ans[cnt][2] = e.flow;                cnt++;            }        }    printf("%d %d\n", flow, cnt);    for (int i = 0; i < cnt; i++)        printf("%d %d %d\n", ans[i][0], ans[i][1], ans[i][2]);}int main() {    while (scanf("%d%d", &n, &m) == 2) {        init();    }    return 0;}

Dinic

#include <cstdio>#include <cstring>#include <algorithm>#include <vector>#include <queue>using namespace std;#define N 1010#define INF 0x3f3f3f3fstruct Edge{    int from, to, cap, flow;    Edge() {}    Edge(int from, int to, int cap, int flow) : from(from), to(to), cap(cap), flow(flow) {}};struct Dinic{    int n, m, s, t;    vector<Edge> edges;    vector<int> G[N];    bool vis[N];    int d[N], cur[N];    void init(int n) {        this->n = n;        for (int i = 0; i <= n; i++) {            G[i].clear();        }        edges.clear();    }    void AddEdge(int from, int to, int cap) {        edges.push_back(Edge(from, to, cap, 0));        edges.push_back(Edge(to, from, 0, 0));        int m = edges.size();        G[from].push_back(m - 2);        G[to].push_back(m - 1);    }     bool BFS() {        memset(vis, 0, sizeof(vis));        queue<int> Q;        Q.push(s);        vis[s] = 1;        d[s] = 0;        while (!Q.empty()) {            int u = Q.front();            Q.pop();            for (int i = 0; i < G[u].size(); i++) {                Edge &e = edges[G[u][i]];                if (!vis[e.to] && e.cap > e.flow) {                    vis[e.to] = true;                    d[e.to] = d[u] + 1;                    Q.push(e.to);                }            }        }        return vis[t];    }    int DFS(int x, int a) {        if (x == t || a == 0)            return a;        int flow = 0, f;        for (int i = cur[x]; i < G[x].size(); i++) {            Edge &e = edges[G[x][i]];            if (d[x] + 1 == d[e.to] && (f = DFS(e.to, min(a, e.cap - e.flow))) > 0) {                e.flow += f;                edges[G[x][i] ^ 1].flow -= f;                flow += f;                a -= f;                if (a == 0)                    break;            }        }        return flow;    }    int Maxflow(int s, int t) {        this->s = s; this->t = t;        int flow = 0;        while (BFS()) {            memset(cur, 0, sizeof(cur));            flow += DFS(s, INF);        }        return flow;    }};Dinic dinic;#define M 70#define P 20int in[M][P], out[M][P], f[M];int n, m;bool NullJudge(int cur) {    for (int i = 1; i <= n; i++)        if (in[cur][i] == 1)            return false;    return true;}bool FullJudge(int cur) {    for (int i = 1; i <= n; i++)        if (!out[cur][i])            return false;    return true;}bool connect(int x, int y) {    for (int i = 1; i <= n; i++)        if (out[x][i] + in[y][i] == 1)            return false;    return true;}void init() {    for (int i = 1; i <= m; i++) {        scanf("%d", &f[i]);        for (int j = 1; j <= n; j++)            scanf("%d", &in[i][j]);        for (int j = 1; j <= n; j++)            scanf("%d", &out[i][j]);    }    int s = 2 * m + 1;    int t = 2 * m + 2;    dinic.init(t);    for (int i = 1; i <= m; i++) {        dinic.AddEdge(i, i + m, f[i]);        if (NullJudge(i))            dinic.AddEdge(s, i, f[i]);        if (FullJudge(i))            dinic.AddEdge(i + m, t, f[i]);        for (int j = 1; j <= m; j++)             if (i != j && connect(i, j))                dinic.AddEdge(i + m, j, f[i]);    }    int ans[M][P];    int flow = dinic.Maxflow(s, t);    int cnt = 0;    for (int i = m + 1; i <= m + m; i++)        for (int j = 0; j < dinic.G[i].size(); j++) {            int v = dinic.G[i][j];            Edge &e = dinic.edges[v];            if (e.flow > 0 && e.to <= m) {                ans[cnt][0] = i - m;                ans[cnt][1] = e.to;                ans[cnt][2] = e.flow;                cnt++;            }        }    printf("%d %d\n", flow, cnt);    for (int i = 0; i < cnt; i++)        printf("%d %d %d\n", ans[i][0], ans[i][1], ans[i][2]);}int main() {    while (scanf("%d%d", &n, &m) == 2) {        init();    }    return 0;}
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