BZOJ5068: 友好的生物(状压 贪心)

时间：2021-02-10 07:39:02

题意

题目链接

Sol

又是一道神仙题？？。。

把绝对值拆开之后状压前面的符号？。。

下界显然，但是上界为啥是对的呀qwq。。

#include<bits/stdc++.h>

using namespace std;

const int MAXN = 1e6 + 10;

inline int read() {

    char c = getchar(); int x = 0, f = 1;

    while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}

    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();

    return x * f;

}

int N, K, C[MAXN], ans;

struct Node {

	int v[6], vk;

	bool operator < (const Node &rhs) const {

		return vk < rhs.vk;

	}

}a[MAXN];

int main() {

	N = read(); K = read() - 1;

	for(int i = 0; i <= K; i++) C[i] = read();

	for(int i = 1; i <= N; i++) {

		for(int j = 0; j < K; j++) a[i].v[j] = read() * C[j]; a[i].vk = read() * C[K];

	}

	sort(a + 1, a + N + 1);

	for(int sta = 0; sta < (1 << K); sta++) {

		int mn = 1e9 + 10;

		for(int i = 1; i <= N; i++) {

			int now = 0;

			for(int j = 0; j < K; j++)

				now += (sta >> j & 1) ? -a[i].v[j] : a[i].v[j];

			now -= a[i].vk;

			ans = max(ans, now - mn);

			mn = min(now, mn);

		}

	}

	cout << ans;

	return 0;

}

/*

5 3

1 2 3

-5 3 2

-2 3 0

0 5 9

3 4 -1

-10 -11 7

*/

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