题目链接:https://vjudge.net/contest/342824#problem/G
题目大意:
// UVa10498 Happiness!
// Rujia Liu
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cassert>
using namespace std;
// 改进单纯性法的实现
// 参考:http://en.wikipedia.org/wiki/Simplex_algorithm
// 输入矩阵a描述线性规划的标准形式。a为m+1行n+1列,其中行0~m-1为不等式,行m为目标函数(最大化)。列0~n-1为变量0~n-1的系数,列n为常数项
// 第i个约束为a[i][0]*x[0] + a[i][1]*x[1] + ... <= a[i][n]
// 目标为max(a[m][0]*x[0] + a[m][1]*x[1] + ... + a[m][n-1]*x[n-1] - a[m][n])
// 注意:变量均有非负约束x[i] >= 0
const int maxm = 500; // 约束数目上限
const int maxn = 500; // 变量数目上限
const double INF = 1e100;
const double eps = 1e-10;
struct Simplex {
int n; // 变量个数
int m; // 约束个数
double a[maxm][maxn]; // 输入矩阵
int B[maxm], N[maxn]; // 算法辅助变量
void pivot(int r, int c) {
swap(N[c], B[r]);
a[r][c] = 1 / a[r][c];
for(int j = 0; j <= n; j++) if(j != c) a[r][j] *= a[r][c];
for(int i = 0; i <= m; i++) if(i != r) {
for(int j = 0; j <= n; j++) if(j != c) a[i][j] -= a[i][c] * a[r][j];
a[i][c] = -a[i][c] * a[r][c];
}
}
bool feasible() {
for(;;) {
int r, c;
double p = INF;
for(int i = 0; i < m; i++) if(a[i][n] < p) p = a[r = i][n];
if(p > -eps) return true;
p = 0;
for(int i = 0; i < n; i++) if(a[r][i] < p) p = a[r][c = i];
if(p > -eps) return false;
p = a[r][n] / a[r][c];
for(int i = r+1; i < m; i++) if(a[i][c] > eps) {
double v = a[i][n] / a[i][c];
if(v < p) { r = i; p = v; }
}
pivot(r, c);
}
}
// 解有界返回1,无解返回0,无界返回-1。b[i]为x[i]的值,ret为目标函数的值
int simplex(int n, int m, double x[maxn], double& ret) {
this->n = n;
this->m = m;
for(int i = 0; i < n; i++) N[i] = i;
for(int i = 0; i < m; i++) B[i] = n+i;
if(!feasible()) return 0;
for(;;) {
int r, c;
double p = 0;
for(int i = 0; i < n; i++) if(a[m][i] > p) p = a[m][c = i];
if(p < eps) {
for(int i = 0; i < n; i++) if(N[i] < n) x[N[i]] = 0;
for(int i = 0; i < m; i++) if(B[i] < n) x[B[i]] = a[i][n];
ret = -a[m][n];
return 1;
}
p = INF;
for(int i = 0; i < m; i++) if(a[i][c] > eps) {
double v = a[i][n] / a[i][c];
if(v < p) { r = i; p = v; }
}
if(p == INF) return -1;
pivot(r, c);
}
}
};
//////////////// 题目相关
#include<cmath>
Simplex solver;
int main() {
int n, m;
while(scanf("%d%d", &n, &m) == 2) {
for(int i = 0; i < n; i++) scanf("%lf", &solver.a[m][i]); // 目标函数
solver.a[m][n] = 0; // 目标函数常数项
for(int i = 0; i < m; i++)
for(int j = 0; j < n+1; j++)
scanf("%lf", &solver.a[i][j]);
double ans, x[maxn];
assert(solver.simplex(n, m, x, ans) == 1);
ans *= m;
printf("Nasa can spend %d taka.\n", (int)floor(ans + 1 - eps));
}
return 0;
}