POJ 2236 Wireless Network（并查集）

题目链接：Wireless Network

每个点用一个标记表示修没修好，然后每次和距离小于d的进行并查集即可

代码：

#include <stdio.h>#include <string.h>#include <math.h>const int N = 1005;int n, parent[N];double d;struct Point {    int x, y, vis;} p[N];double dis(Point a, Point b) {    return sqrt((b.x - a.x) * (b.x - a.x) + (b.y - a.y) * (b.y - a.y));}void init() {    memset(p, 0, sizeof(p));    for (int i = 1; i <= n; i++)parent[i] = i;}int find(int x) {    if (x == parent[x])return x;    return parent[x] = find(parent[x]);}int main() {    while (~scanf("%d%lf", &n, &d)) {init();for (int i = 1; i <= n; i++)    scanf("%d%d", &p[i].x, &p[i].y);char q[2]; int a, b;while (~scanf("%s", q)) {    if (q[0] == 'O') {scanf("%d", &a);p[a].vis = 1;for (int i = 1; i <= n; i++) {    if (p[i].vis && (dis(p[i], p[a]) < d || fabs(dis(p[i], p[a]) - d) < 1e-9)) {int pa = find(i);int pb = find(a);if (pa != pb)    parent[pa] = pb;    }}    }    else {scanf("%d%d", &a, &b);int pa = find(a);int pb = find(b);if (pa == pb) {    printf("SUCCESS\n");}else {    printf("FAIL\n");}    }}    }    return 0;}