uva 216 - Getting in Line

开始还以为最小生成树，结果最多8个节点，明显是要暴力枚举。

先递归生成每种排列，计算距离总和，记录下最小的，最后输出。

 

#include<stdio.h>
#include<math.h>
#include<string.h>

typedef struct Point {
	int x;
	int y;
} Point;

Point point[8];
int n;
double minLen;
int minPerm[8];
int perm[8];

void permu(int cur) {
	if (cur == n) {
		int i;
		/*		for (i = 0; i < n; i++)
		 printf("%d ", perm[i]);
		 printf("\n");
		 */
		double curLen = 0;
		for (i = 0; i < n - 1; i++) {

			curLen += sqrt(
					pow(point[perm[i]].x - point[perm[i + 1]].x, 2)
							+ pow(point[perm[i]].y - point[perm[i + 1]].y, 2))
					+ 16;
		}

		if (curLen < minLen) {
			minLen = curLen;
			memcpy(minPerm, perm, sizeof(perm));
		}

		return;
	} else {
		int i, j;
		for (i = 0; i < n; i++) {
			int exist = 0;
			for (j = 0; j < cur; j++)
				if (perm[j] == i) {
					exist = 1;
					break;
				}
			if (!exist) {
				perm[cur] = i;
				permu(cur + 1);
			}
		}
	}
}

int main() {
	int cases = 1;
	while (scanf("%d", &n)) {
		if (n == 0)
			break;
		minLen = 0x7fffffff;
		memset(minPerm, 0, sizeof(minPerm));

		int i;
		for (i = 0; i < n; i++)
			scanf("%d%d", &point[i].x, &point[i].y);

		permu(0);
		printf("**********************************************************\n");
		printf("Network #%d\n", cases++);

		double len = 0;
		for (i = 0; i < n - 1; i++) {
			len = sqrt(
					pow(point[minPerm[i]].x - point[minPerm[i + 1]].x, 2)
							+ pow(point[minPerm[i]].y - point[minPerm[i + 1]].y,
									2)) + 16;
			printf(
					"Cable requirement to connect (%d,%d) to (%d,%d) is %.2lf feet.\n",
					point[minPerm[i]].x, point[minPerm[i]].y,
					point[minPerm[i + 1]].x, point[minPerm[i + 1]].y, len);
		}

		printf("Number of feet of cable required is %.2lf.\n", minLen);

	}
	return 0;
}