HDU 5441 离线处理+并查集

并查集+离线处理

代码：

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <vector>#include <algorithm>using namespace std;#define maxm 100002#define maxn 20002#define maxq 5002int set[maxn];int size[maxn];//结点数struct que{int q, i;long long ans;}ques[maxq];bool cmpp1(que a,que b){return a.q < b.q;}bool cmpp2(que a, que b){return a.i < b.i;}struct edge{int v, i, j;void init(int a, int b, int x){if (a < b){i = a; j = b;}else{i = b; j = a;}v = x;}};edge a1[maxm], a2[maxm];bool cmp1(edge a, edge b){if (a.i < b.i)return true;else if (a.i == b.i&&a.j < b.j)return true;elsereturn false;}bool cmp2(edge a, edge b){return a.v < b.v;}int upperbound(edge *A, int x, int y, int v){int m;while (x < y){m = x + (y - x) / 2;if (A[m].v <= v)x = m + 1;elsey = m;}return x;}void init_set(){for (int i = 0; i<maxn; ++i){set[i] = i;size[i] = 1;}}int findSet(int x)//路径压缩{if (x == set[x])return x;elsereturn set[x] = findSet(set[x]);}void unionSet(int x, int y)//启发式合并{int fx = findSet(x);int fy = findSet(y);if (fy == fx)return;if (size[fx] >= size[fy]){size[fx] += size[fy];set[fy] = fx;}else{size[fy] += size[fx];set[fx] = fy;}}int main(){//freopen("input.txt", "r", stdin);int T;scanf("%d", &T);while (T--){int n, m, q, a, b, c;long long ans = 0, t;scanf("%d%d%d", &n, &m, &q);for (int i = 0; i < m; ++i){scanf("%d%d%d", &a, &b, &c);a1[i].init(a, b, c);}sort(a1, a1 + m, cmp1);a = 0, b = 0;int m2 = 0;for (int i = 0; i < m; ++i){if (a1[i].i == a&&a1[i].j == b)a2[m2 - 1].v = min(a1[i].v, a2[m2 - 1].v);else{a2[m2++] = a1[i];a = a1[i].i, b = a1[i].j;}}sort(a2, a2 + m2, cmp2);for (int i = 0; i < q; ++i){scanf("%d", &ques[i].q);ques[i].i = i;ques[i].ans = 0;}sort(ques, ques + q, cmpp1);init_set(); a = 0;for (int i = 0; i < q; ++i){b = upperbound(a2, 0, m2, ques[i].q);//printf("b %d\n", b);for (int j = a; j < b; ++j){unionSet(a2[j].i, a2[j].j);}for(int j = 1; j <= n; ++j){if (set[j] == j&&size[j] > 1){t = size[j];ques[i].ans += t*(t - 1);//printf("t %lld\n", t);//printf("ans %lld\n", ques[i].ans);}}a = b;}sort(ques, ques + q, cmpp2);for (int i = 0; i < q; ++i)printf("%lld\n", ques[i].ans);}//system("pause");//while (1);return 0;}