Ural_1671. Anansi's Cobweb(并查集)

　　/*思路参考大牛，我脑袋被lv踢了，居然想到用数状数组写。。。
思路：并查集，先把不许要删的边用并查集合并，然后把需要删的边逆序加入到并查集中。。。。

My Code：*/

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

const int N = 100005;

struct node {
int s;
int e;
}g
;

int parent
;
int c
;
int ans
;
int Rank
;
bool vis
;

void init(int n) {
for(int i = 1; i <= n; i++) {
parent[i] = i;
Rank[i] = 0;
vis[i] = false;
}
}

int find(int x) {
int k, r, j;
r = x; k = x;
while(r != parent[r]) {
r = parent[r];
}
while(k != r) {
j = parent[k];
parent[k] = r;
k = j;
}
return r;
}

void union_set(int x, int y) {
x = find(x);
y = find(y);
if(x == y)    return;
if(Rank[x] > Rank[y])    parent[y] = x;
else {
parent[x] = y;
if(Rank[x] == Rank[y])    ++ Rank[y];
}
}

int main() {
//freopen("data.in", "r", stdin);

int n, m, i, k, cnt;
while(~scanf("%d%d", &n, &m)) {
init(n); cnt = 0;
for(i = 1; i <= m; i++) {
scanf("%d%d", &g[i].s, &g[i].e);
vis[i] = true;
}

scanf("%d", &k);
for(i = 0; i < k; i++) {
scanf("%d", &c[i]);
vis[c[i]] = false;
}

for(i = 1; i <= m; i++) {
if(!vis[i])    continue;
if(find(g[i].s) != find(g[i].e)) {
union_set(g[i].s, g[i].e);
cnt++;
}
}

for(i = k-1; i >= 0; i--) {
ans[i] = n-cnt;
if(find(g[c[i]].s) != find(g[c[i]].e)) {
union_set(g[c[i]].s, g[c[i]].e);
cnt++;
}
}

for(i = 0; i < k; i++) {
printf("%d", ans[i]);
if(i == k-1)    putchar('\n');
else    putchar('');
}
}
return 0;
}