PAT a1127题解

来源：互联网发布：永宏编程手册编辑：程序博客网时间：2024/06/14 06:57
#include<cstdio>  #include<vector>  #include<queue>  using namespace std;  const int maxn = 35;  int in[maxn], post[maxn];  struct Node  {      int data;      int depth;      Node*l, *r;      Node():l(NULL),r(NULL){}  };  int N, maxdepth = -1;  Node*create(int i1, int i2, int p1, int p2)  {      if (i1 > i2 || p1 > p2)return NULL;      Node*root = new Node();      root->data = post[p2];      int k;      for (int i = i1; i <= i2; i++)      {          if (in[i] == root->data)          {              k = i; break;          }      }      root->l = create(i1, k - 1, p1, p1 + k - 1 - i1);      root->r = create(k+1, i2, p2-1-(i2-k-1), p2-1);      return root;  }  vector<int> nodes[maxn];  void BFS(Node*root)  {      queue<Node*>Q;      root->depth = 0;      Q.push(root);      while (!Q.empty())      {          Node*f = Q.front();          Q.pop();          maxdepth = max(maxdepth, f->depth);          nodes[f->depth].push_back(f->data);          if (f->l)          {              f->l->depth = f->depth + 1;              Q.push(f->l);          }          if (f->r)          {              f->r->depth = f->depth + 1;              Q.push(f->r);          }      }  }  int main()  {      scanf("%d", &N);      for (int i = 0; i < N; i++)          scanf("%d", &in[i]);      for (int i = 0; i < N; i++)          scanf("%d", &post[i]);      Node*root = NULL;      bool first = true;      root = create(0, N - 1, 0, N - 1);      BFS(root);      for (int i = 0; i <= maxdepth; i++)      {          if (i % 2 == 0)          {              for (int j = 0; j < nodes[i].size(); j++)              {                  if (first)                  {                      first = false;                      printf("%d", nodes[i][nodes[i].size() - 1 - j]);                  }                  else printf(" %d", nodes[i][nodes[i].size() - 1 - j]);              }          }          else          {              for (int j = 0; j < nodes[i].size(); j++)              {                  if (first)                  {                      first = false;                      printf("%d", nodes[i][j]);                  }                  else printf(" %d", nodes[i][j]);              }          }      }      return 0;  }
阅读全文
1 0