请问记忆化搜索DFS为什么只有40分?
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请问记忆化搜索DFS为什么只有40分?
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zhoubaobei楼主2022/12/6 00:10
// https://www.luogu.com.cn/problem/P3916
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'
#define INF 0x3f3f3f3f
const int N = 1e6 + 10;

int n, m;
int idx, h[N], e[N], ne[N];
bool st[N];
int ans[N];

void add(int a, int b) {
  e[idx] = b;
  ne[idx] = h[a];
  h[a] = idx++;
}

int dfs(int cur) {
  if (st[cur]) return ans[cur];
  st[cur] = 1;
  int res = cur;
  for (int i = h[cur]; i != -1; i = ne[i]) {
    int j = e[i];
    res = max(res, dfs(j));
  }
  ans[cur] = res;
  return res;
}

void solve() {
  cin >> n >> m;
  memset(h, -1, sizeof(int) * (n + 3));
  while (m--) {
    int a, b;
    cin >> a >> b;
    add(a, b);
  }
  for (int i = 1; i <= n; i++) {
    dfs(i);
  }
  for (int i = 1; i <= n; i++) cout << ans[i] << ' ';
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);

  int t;
  // cin >> t;
  t = 1;
  while (t--) {
    solve();
  }
  return 0;
}

为什么记忆化搜索只有40分呢?

2022/12/6 00:10
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