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  • 线性规划模板

    前段时间我参加华为比赛学习的线性规划
    虽然现在看来没有卵用
    将模板贴一下

    #include<cmath>
    #include<map>
    #include<iostream>
    #include<cstring>
    #include<cstdio>
    #include<set>
    #include<vector>
    #include<algorithm>
    using namespace std;
    typedef long long ll;
    const int MAXN = 1005;
    const double INF = 1e10;
    const double eps = 1e-7;
    
    int n,m; // 行, 列
    double c[MAXN]; double b[MAXN]; double a[MAXN][MAXN]; double x[MAXN*2]; double v; int N[MAXN], B[MAXN];
    int ans;
    
    int cnt = 0;
    void debug(int pos , int flor) {
        if(cnt < 10) {
            cnt ++;
        }else return ;
        printf("pos = %d, flor = %d
    ",pos,flor);
        printf("%d %d %.2f
    ",n,m,v);
    
        for(int i = 1; i <= m; ++i)
            printf("%.2f ", c[i]); printf("
    ");
    
        for(int i = 1; i <= n; ++i) {
            printf("%.2f ",b[i]);
            for(int j = 1; j <= m; ++j) {
                printf("%.2f ",a[i][j]);
            }
            printf("
    ");
        }
        for(int i = 1; i <= n; ++i) printf("%d ",B[i]); printf("
    ");
        for(int i = 1; i <= m; ++i) printf("%d ",N[i]); printf("
    ");
    //  for(int i = 1; i <= n+m; ++i) printf("%.2f ",x[i]); printf("
    
    ");
    }
    
    
    int equal(double a, double b) {
        double tt = fabs(b-a);
        if(tt < eps) return 1;
        else return 0;
    }
    void priov(int l, int e) { // 第l行,第e列
        b[l] /= a[l][e];
        for(int i = 1; i <= m; ++i) {
            if(i != e) {
                a[l][i] /= a[l][e];
            }
        }    
        a[l][e] = 1/a[l][e];
        for(int i = 1; i <= n; ++i) {
            if(i != l && fabs(a[i][e]) > eps) {
                b[i] -= b[l] * a[i][e];
                for(int j = 1; j <= m; ++j) {
                    if(j != e) {
                        a[i][j] -= a[i][e] * a[l][j];
                    }
                }
                a[i][e] = -a[i][e] * a[l][e];
            }
        }
        v += c[e] * b[l];
        for(int i = 1; i <= m; ++i) {
            if(i != e) {
                c[i] -= c[e] * a[l][i];
            }
        }
        c[e] = -c[e] * a[l][e];
    }
    double simple(){
        while(1) {
            int l,e = 0;
            for(int i = 1; i <= m; ++i) {
                if(c[i] > eps) {
                    e = i; break;
                }   
            }
            if(!e) return v;
            double minn = INF;
            for(int i = 1; i <= n; ++i) {
                if(a[i][e] > eps && minn > b[i]/a[i][e]) {
                    minn = b[i]/a[i][e]; l = i; 
                }
            }
            if(minn == INF) return minn;
            priov(l, e);
            swap(B[l], N[e]);       
        }
    }
    int initsimplex() { // 找到一个初始可行解
        // 备份一些信息
        int _m = m; double _v = v;
        int _N[m+5]; int _c[m+5]; 
        for(int i = 1; i <= m; ++i) _N[i] = N[i];
        for(int i = 1; i <= m; ++i) _c[i] = c[i];
    
        int id, minn = INF;
        for(int i = 1; i <= n; ++i) 
            if(b[i] < minn) {
                id = i; minn = b[i];
            }
    
        if(b[id] >= 0) return 1;
        //最初形式不满足条件,就需要寻找一个
    
        m ++;
        v = 0;
        for(int i = 1; i <= m; ++i)  c[i] = 0; c[m] = -1;
        for(int i = 1; i <= n; ++i) a[i][m] = -1;
    
        N[m] = 0;
    //  debug(2, 1);
        printf("%d %d
    ",id,m);
        priov(id, m);
        swap(B[id], N[m]);
        debug(3, 1);
        simple();
        debug(4,1);
        if( equal(v, 0) == 0) return 0;
        //现将生成的新松弛型中的x0项删去
        for(int i = 1; i <= n; ++i) {
            if(B[i] == 0) {
                int pos;
                for(int j = 1; j <= m; ++j) {
                    if(a[i][j] != 0) {
                        pos = j;
                    }
                }
                priov(i, pos);
                swap(B[i], N[pos]);
                break;
            }
        }
        for(int i = 1; i <= n; ++i) {
            int fl = 0;
            for(int j = 1; j <= m; ++j) {
                if(N[j] == 0) fl = 1;
                if(fl) {
                    a[i][j] = a[i][j+1]; 
                }
            }
        }
    
        int fl = 0;
        for(int i = 1; i <= m; ++i) {
            if(N[i] == 0) fl = 1;
            if(fl) N[i] = N[i+1];
        }
        m --;
        map<int, int> m1; m1.clear();
        map<int, int> m2; m2.clear();
    
        for(int i = 1; i <= n; ++i) m1[B[i]] = i;
        for(int i = 1; i <= m; ++i) m2[N[i]] = i;
        for(int i = 1; i <= m; ++i) c[i] = 0;
        v = _v;
        printf("%.3f
    ",v);
        for(int i = 1; i <= _m; ++i) {
            if(m1.count(_N[i])) {
                int tt = m1[_N[i]];
                for(int j = 1; j <= m; ++j) {
                    c[j] -= _c[i] * a[tt][j];
                }
                v += _c[i] * b[tt];
            }else {
                c[m2[_N[i]]] += _c[i];
            } 
        }
        return 1;
    }
    void solve(){
        while(~scanf("%d %d",&n,&m)) {
            ans = -1;
            scanf("%lf",&v);
            for(int i = 1; i <= m; ++i) scanf("%lf",&c[i]);
            for(int i = 1; i <= n; ++i) {
                scanf("%lf",&b[i]);
                for(int j = 1; j <= m; ++j) {
                    scanf("%lf",&a[i][j]);
                }
            }
            for(int i = 1; i <= m; ++i) N[i] = i;
            for(int i = 1; i <= n; ++i) B[i] = i+m;
            set<int> st;
        //  for(int i = 1; i <= m; ++i) st.insert(N[i]);
    
            int tt = initsimplex();
            for(int i = 1; i <= m; ++i) st.insert(N[i]);
            if(!tt) {
                printf("there is none true answer!
    ");
                return;
            }
            debug(1,1);
            simple();
            memset(x, 0, sizeof(x));
            for(int i = 1; i <= n; ++i) {
                if(st.find(B[i]) != st.end()) {
                    x[B[i]] = b[i];
                }
            }
    
            debug(1, 1);
            printf("ans = %d 
    ", ans);
        }
    }
    int main(){
        solve();
        return 0;
    }
    
    /*
       2 2 
       0
       3 13
       40 2 9
       82 11 -8
    
       5 2 0.00
       3.00 13.00 
       40.00 2.00 9.00 
       82.00 11.00 -8.00 
       9.00 1.00 0.00 
       2.00 0.00 1.00 
       -9.00 -1.00 0.00
    
       4 2 0.00
       3.00 13.00 
       40.00 2.00 9.00 
       82.00 11.00 -8.00 
       9.00 1.00 0.00 
       -3.00 0.00 -1.00 
    */
    
    
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  • 原文地址:https://www.cnblogs.com/Basasuya/p/8433714.html
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