前序和中序+后序和中序
/**由前序遍历和中序遍历得到层次遍历序列**/ #include<iostream> #include<cstdio> #include<cstring> #include<stack> #include<queue> #include<algorithm> using namespace std; const int maxn=107; int T[maxn], n; int preorder[maxn], inorder[maxn]; void BuildTree(int root, int start, int ends, int index) { int mid=start; if(start>ends || root>n)return; T[index]=preorder[root]; while(inorder[mid]!=preorder[root] && mid<ends) mid++; BuildTree(root+1, start, mid-1, index*2); BuildTree(root+1+mid-start, mid+1, ends, index*2+1); } int main() { while(~scanf("%d", &n)) { for(int i=1; i<=n; i++) scanf("%d", &preorder[i]); for(int i=1; i<=n; i++) scanf("%d", &inorder[i]); BuildTree(1, 1, n, 1); for(int i=1; i<=2*n+1; i++) { if(T[i]!=0) printf("%d ", T[i]); } printf("\n"); } return 0; } /* 7 4 1 3 2 6 5 7 1 2 3 4 5 6 7 */ /**由后序遍历和中序遍历得到层次遍历序列**/ #include<iostream> #include<cstdio> #include<cstring> #include<stack> #include<queue> #include<algorithm> using namespace std; const int maxn=107; int T[maxn], n; int posorder[maxn], inorder[maxn]; void BuildTree(int root, int start, int ends, int index) { if(start>ends || root>n)return; int mid=start; T[index]=posorder[root]; while(inorder[mid]!=posorder[root] && mid<ends) mid++; BuildTree(root-1-ends+mid, start, mid-1, index*2); BuildTree(root-1, mid+1, ends, index*2+1); } int main() { while(~scanf("%d", &n)) { for(int i=1; i<=n; i++) scanf("%d", &posorder[i]); for(int i=1; i<=n; i++) scanf("%d", &inorder[i]); BuildTree(n, 1, n, 1); for(int i=1; i<=2*n+1; i++) { if(T[i]!=0) printf("%d ", T[i]); } printf("\n"); } return 0; } /* 7 2 3 1 5 7 6 4 1 2 3 4 5 6 7 */