• ZOJ1157, POJ1087,UVA 753 A Plug for UNIX (最大流)


    链接 : http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?

    id=26746

    题目意思有点儿难描写叙述 用一个别人描写叙述好的。




    我的建图方法:一个源点一个汇点,和全部种类的插座。输入的n个插座直接与源点相连,容量为1,m个物品输入里 记录每一个插座相应的物品个数。物品数然后大于0的插座直接连到汇点。意味着终于的物品仅仅能由这些插座流出。中间的插座转换容量都是INF  a b表示  不管多少b都能够选择转化到a。


    /*--------------------- #headfile--------------------*/
    #include <algorithm>
    #include <iostream>
    #include <sstream>
    #include <cstring>
    #include <cstdlib>
    #include <cassert>
    #include <cstdio>
    #include <vector>
    #include <cmath>
    #include <queue>
    #include <stack>
    #include <set>
    #include <map>
    /*----------------------#define----------------------*/
    #define DRII(X,Y) int (X),(Y);scanf("%d%d",&(X),&(Y))
    #define EXP 2.7182818284590452353602874713527
    #define CASET int _;cin>>_;while(_--)
    #define RII(X, Y) scanf("%d%d",&(X),&(Y))
    #define DRI(X) int (X);scanf("%d", &X)
    #define mem(a,b) memset(a,b,sizeof(a))
    #define rep(i,n) for(int i=0;i<n;i++)
    #define ALL(X) (X).begin(),(X).end()
    #define INFL 0x3f3f3f3f3f3f3f3fLL
    #define RI(X) scanf("%d",&(X))
    #define SZ(X) ((int)X.size())
    #define PDI pair<double,int>
    #define rson o<<1|1,m+1,r
    #define PII pair<int,int>
    #define MAX 0x3f3f3f3f
    #define lson o<<1,l,m
    #define MP make_pair
    #define PB push_back
    #define SE second
    #define FI first
    typedef long long ll;
    template<class T>T MUL(T x,T y,T P){T F1=0;while(y){if(y&1){F1+=x;if(F1<0||F1>=P)F1-=P;}x<<=1;if(x<0||x>=P)x-=P;y>>=1;}return F1;}
    template<class T>T POW(T x,T y,T P){T F1=1;x%=P;while(y){if(y&1)F1=MUL(F1,x,P);x=MUL(x,x,P);y>>=1;}return F1;}
    template<class T>T gcd(T x,T y){if(y==0)return x;T z;while(z=x%y)x=y,y=z;return y;}
    #define DRIII(X,Y,Z) int (X),(Y),(Z);scanf("%d%d%d",&(X),&(Y),&(Z))
    #define RIII(X,Y,Z) scanf("%d%d%d",&(X),&(Y),&(Z))
    const double pi = acos(-1.0);
    const double eps = 1e-6;
    const ll mod = 1000000007ll;
    const int M = 1005;
    const int N = 605;
    using namespace std;
    
    /*----------------------Main-------------------------*/
    struct Edge {
        int to, c, rev;
        Edge() {}
        Edge(int _to, int _c, int _rev) {
            to = _to, c = _c, rev = _rev;
        }
    };
    vector<Edge> G[N];
    int lv[N], iter[N];
    int n, m;
    void BFS(int s) {
        mem(lv, -1);
        queue<int> q;
        lv[s] = 0;
        q.push(s);
        while(!q.empty()) {
            int v = q.front(); q.pop();
            for(int i = 0; i < SZ(G[v]); i++) {
                Edge &e = G[v][i];
                if(e.c > 0 && lv[e.to] < 0) {
                    lv[e.to] = lv[v] + 1;
                    q.push(e.to);
                }
            }
        }
    }
    int dfs(int v, int t, int f) {
        if(v == t) return f;
        for(int &i = iter[v]; i < SZ(G[v]); i++) {
            Edge &e = G[v][i];
            if(e.c > 0 && lv[v] < lv[e.to]) {
                int d = dfs(e.to, t, min(f, e.c));
                if(d > 0) {
                    e.c -= d;
                    G[e.to][e.rev].c += d;
                    return d;
                }
            }
        }
        return 0;
    }
    int MF(int s, int t) {
        int res = 0;
        for( ; ; ) {
            BFS(s);
            if(lv[t] < 0) return res;
            mem(iter, 0);
            int f;
            while((f = dfs(s, t, 1e9)) > 0) {
                res += f;
            }
        }
    }
    void add(int from, int to, int c) {
        G[from].PB( Edge(to, c, SZ(G[to])) );
        G[to].PB( Edge(from, 0, SZ(G[from]) - 1) );
    }
    int num[N];
    int FF = 0;
    void solve() {
        if(FF) puts(""); FF = 1;
        RI(n);
        for(int i = 0; i < 300; i++) G[i].clear();
        mem(num, 0);
        int s = 0, k = 0;
        map<string, int> vis;
        for(int i = 1; i <= n; i++) {
            string s1; cin >> s1;
            vis[s1] = ++k;
            add(s, i, 1);
        }
        RI(m);
        for(int i = 1; i <= m; i++) {
            string s1, s2;
            cin >> s1 >> s2;
            if(vis[s2] == 0) vis[s2] = ++k;
            num[ vis[s2] ]++;
        }
        int t = k + 1;
        for(int i = 1; i <= k; i++) {
            if(num[i]) add(i, t, num[i]);
        }
        DRI(x);
        k++;
        for(int i = 1; i <= x; i++) {
            string s1, s2;
            cin >> s1 >> s2;
            if(vis[s2] == 0) vis[s2] = ++k;
            if(vis[s1] == 0) vis[s1] = ++k;
            int u = vis[s2], v = vis[s1];
            add(u, v, 1e9);
        }
        int ans = MF(s, t);
        printf("%d
    ", m - ans);
    }
    
    int main() {
    //    freopen("in.txt", "r", stdin);
    //    freopen("out.txt", "w", stdout);
        CASET
        solve();
        return 0;
    }
    


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  • 原文地址:https://www.cnblogs.com/mfmdaoyou/p/7259551.html
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