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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#268776#7753. Energy DistributionFISHER_WA 0ms3948kbC++201.3kb2023-11-28 21:02:252023-11-28 21:02:25

Judging History

你现在查看的是最新测评结果

  • [2024-10-31 10:22:30]
  • hack成功,自动添加数据
  • (/hack/1089)
  • [2023-11-28 21:02:25]
  • 评测
  • 测评结果:WA
  • 用时:0ms
  • 内存:3948kb
  • [2023-11-28 21:02:25]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
const int maxn = 10;
int w[maxn + 5][maxn + 5];
double m[maxn + 5][maxn + 5], x[maxn + 5];
void gauss(int n) {
	for (int i = 0; i <= n; i++) {
		double mx = 0; int id;
		for (int j = i; j <= n; j++)
			if (abs(m[j][i]) > mx) mx = abs(m[j][i]), id = j;
		if (mx == 0) continue;
		swap(m[i], m[id]);
		for (int j = 0; j <= n; j++)
			if (i != j) {
				double v = m[j][i] / m[i][i];
				for (int k = 0; k <= n + 1; k++) m[j][k] -= m[i][k] * v;
			}
	}
	for (int i = 0; i <= n; i++) x[i] = m[i][n + 1] / m[i][i];
}
int main() {
	int n;
	scanf("%d", &n);
	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++) scanf("%d", &w[i][j]);
	int S = 1 << n;
	double ans = 0;
	for (int s = 1; s < S; s++) {
		for (int i = 0; i <= n; i++) {
			x[i] = 0;
			for (int j = 0; j <= n + 1; j++) m[i][j] = 0;
		}
		for (int i = 0; i < n; i++)
			if ((s >> i) & 1) {
				for (int j = 0; j < n; j++)
					if (i != j && ((s >> j) & 1)) m[i][j] = w[i][j];
				m[i][n] = -1, m[n][i] = 1;
			}
		m[n][n + 1] = 1;
		gauss(n);
		double sum = 0;
		for (int i = 0; i < n; i++)
			if (0 > x[i] || x[i] > 1) goto ed;
		for (int i = 0; i < n; i++)
			for (int j = i + 1; j < n; j++) sum += x[i] * x[j] * w[i][j];
		ans = max(ans, sum);
		ed:;
	}
	printf("%.7lf", ans);
}

详细

Test #1:

score: 100
Accepted
time: 0ms
memory: 3880kb

input:

2
0 1
1 0

output:

0.2500000

result:

ok found '0.2500000', expected '0.2500000', error '0.0000000'

Test #2:

score: 0
Accepted
time: 0ms
memory: 3812kb

input:

3
0 2 1
2 0 2
1 2 0

output:

0.5714286

result:

ok found '0.5714286', expected '0.5714290', error '0.0000004'

Test #3:

score: 0
Accepted
time: 0ms
memory: 3948kb

input:

3
0 1 2
1 0 1
2 1 0

output:

0.5000000

result:

ok found '0.5000000', expected '0.5000000', error '0.0000000'

Test #4:

score: -100
Wrong Answer
time: 0ms
memory: 3880kb

input:

4
0 3 1 0
3 0 1 0
1 1 0 2
0 0 2 0

output:

0.4285714

result:

wrong answer 1st numbers differ - expected: '0.7500000', found: '0.4285714', error = '0.3214286'