【LOJ】#2108. 「JLOI2015」装备购买

题解

换成long double才过……出题人丧心病狂卡精度

只要按照费用排序从小到大排序，一个个插入线性基，插入的时候加上费用即可

代码

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define enter putchar('\n')
#define space putchar(' ')
//#define ivorysi
using namespace std;
typedef long long int64;
typedef long double db;
typedef unsigned int u32;
template<class T>
void read(T &res) {
    res = 0;char c = getchar();T f = 1;
    while(c < '0' || c > '9') {
	if(c == '-') f = -1;
	c = getchar();
    }
    while(c >= '0' && c <= '9') {
	res = res * 10 + c - '0';
	c = getchar();
    }
    res *= f;
}
template<class T>
void out(T x) {
    if(x < 0) {putchar('-');x = -x;}
    if(x >= 10) out(x / 10);
    putchar('0' + x % 10);
}
int N,M;
db num[505][505];
int id[505],c[505],wh[505],cnt;
int64 ans;
bool cmp(int a,int b) {
    return c[a] < c[b];
}
void Init() {
    read(N);read(M);
    for(int i = 1 ; i <= N ; ++i) {
	for(int j = 1 ; j <= M ; ++j) {
	    scanf("%Lf",&num[i][j]);
	}
    }
    for(int i = 1 ; i <= N ; ++i) {read(c[i]);id[i] = i;}
    sort(id + 1,id + N + 1,cmp);
}
void Solve() {
    for(int i = 1 ; i <= N ; ++i) {
	int u = id[i];
	for(int j = M ; j >= 1 ; --j) {
	    if(fabs(num[u][j]) > 1e-8) {
		if(wh[j]) {
		    for(int k = 1 ; k <= j ; ++k) num[u][k] -= num[u][j] * num[wh[j]][k];
		}
		else {
		    for(int k = 1 ; k <= j ; ++k) num[u][k] /= num[u][j];
		    wh[j] = u;ans += c[u];++cnt;break;
		}
	    }
	}
    }
    out(cnt);space;out(ans);enter;
}
int main() {
#ifdef ivorysi
    freopen("f1.in","r",stdin);
#endif
    Init();
    Solve();
}