127 lines
3.0 KiB
C++
127 lines
3.0 KiB
C++
#pragma comment(linker, "/STACK:16777216")
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#include<stdio.h>
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#include<iostream>
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#include<string.h>
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#include<ctype.h>
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#include<math.h>
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#include<map>
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#include<set>
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#include<vector>
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#include<queue>
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#include<functional>
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#include<string>
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#include<algorithm>
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#include<time.h>
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#include<bitset>
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using namespace std;
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const int maxn = 200005;
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const int maxm = 400005;
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struct Edge
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{
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int v;
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Edge *next;
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}E[maxm], *edges, *H[maxn];
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int tsum[maxn];
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int size[maxn];
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int sum[maxn];
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int dfn[maxn];
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int low[maxn];
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int bcc[maxn];
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int cnt[maxn];
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int fa[maxn];
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int a[maxn];
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int c[maxn];
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int n, m, tcnt, K, dfs_clock, ok;
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void addedges(int u, int v)
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{
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edges->v = v;
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edges->next = H[u];
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H[u] = edges++;
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}
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void init()
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{
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dfs_clock = 0;
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tcnt = 0;
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edges = E;
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for(int i = 0; i <= n; i++) {
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H[i] = 0;
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dfn[i] = low[i] = bcc[i] = cnt[i] = 0;
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}
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}
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void dfs(int u)
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{
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dfn[u] = low[u] = ++dfs_clock;
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for(Edge *e = H[u]; e; e = e->next) if(e->v != fa[u]) {
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int v = e->v;
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if(!dfn[v]) {
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fa[v] = u;
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dfs(v);
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low[u] = min(low[u], low[v]);
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}
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else low[u] = min(low[u], dfn[v]);
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if(fa[v] != u && dfn[u] < dfn[v]) {
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int vn = v;
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bcc[u] = true;
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a[++tcnt] = u;
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do {
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a[++tcnt] = vn;
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bcc[vn] = true;
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vn = fa[vn];
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}while(vn != u);
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}
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}
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}
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void DFS(int u, int f)
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{
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size[u] = 1;
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for(Edge *e = H[u]; e; e = e->next) if(!bcc[e->v] && e->v != f) {
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int v = e->v;
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DFS(v, u);
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size[u] += size[v];
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}
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}
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void work()
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{
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int u, v;
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for(int i = 1; i <= n; i++) {
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scanf("%d", &v);
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addedges(i, v);
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addedges(v, i);
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}
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dfs(1);
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int ans = 0;
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for(int i = tcnt+1; i <= 2 * tcnt; i++) a[i] = a[i - tcnt];
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for(int i = 1; i <= n; i++) if(bcc[i]) DFS(i, i);
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for(int i = 1; i <= n; i++) if(!bcc[i]) cnt[size[i]]++;
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for(int i = 1; i <= n; i++)
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for(int j = i + i; j <= n; j += i)
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cnt[i] += cnt[j];
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for(int i = 1; i <= n; i++) if(n % i == 0) {
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K = i;
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int tt = n / K - cnt[K];
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for(int i = 1; i <= tcnt; i++) sum[i] = size[a[i]] % K;
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for(int i = tcnt + 1; i <= 2 * tcnt; i++) sum[i] = sum[i - tcnt];
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for(int i = 1; i <= 2 * tcnt; i++) sum[i] = (sum[i] + sum[i-1]) % K;
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for(int i = 0; i <= K; i++) c[i] = -1;
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for(int i = 0; i <= 2 * tcnt; i++) {
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if(c[sum[i]] != -1) tsum[i] = tsum[c[sum[i]]] + 1;
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c[sum[i]] = i;
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}
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for(int i = tcnt+1; i <= 2 * tcnt; i++) {
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if(tsum[i] - tsum[i-tcnt] >= tt) {
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ans++;
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break;
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}
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}
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}
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printf("%d\n", ans);
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}
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int main()
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{
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while(scanf("%d", &n) != EOF) {
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init();
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work();
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}
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return 0;
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}
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