2016暑假集训训练2 C题 食物链

带权并查集傻逼题

用拆点方法草过。

拆点代码：

# include <stdio.h>
# include <string.h>
int set[150005], n, k, d;

int find(int x)
{
	int s, temp;
	for (s=x; set[s]>=0; s=set[s])
		;
	while (s != x) {
		temp = set[x];
		set[x] = s;
		x = temp;
	}
	return s;
}

void union_set(int x, int y)
{
	x = find(x); y = find(y);
	int temp = set[x] + set[y];
	if (x != y) {
		if (set[x] > set[y]) {
			set[x] = y;
			set[y] = temp;
		}
		else {
			set[y] = x;
			set[x] = temp;
		}
	}
}

int main (void)
{
	int x, y, cnt=0;
	scanf("%d%d",&n,&k);
	memset(set,-1,sizeof(set));
	while (k--) {
		scanf("%d%d%d",&d,&x,&y);
		if (x>n || y>n) {
			cnt++;
			continue;
		}
		if (d == 1) {
			if (find(x) == find(y+n) || find(x) == find(y+2*n)) {
				cnt++;
			}
			else {
				union_set(x,y);
				union_set(x+n,y+n);
				union_set(x+2*n,y+2*n);
			}
		}
		else {
			if (find(x) == find(y) || find(x) == find(y+2*n))
				cnt++;
			else {
				union_set(x,y+n);
				union_set(x+n,y+n*2);
				union_set(x+n*2,y);
			}
		}
	}
	printf("%d\n",cnt);
	return 0;
}