1086 Tree Traversals Again (25分)

#include<stdio.h>
#include<stack>
#include<cstring>
#include<algorithm>
using namespace std;
int n;
int in[50], pre[50];
struct node {
    int data;
    node* lchild;
    node* rchild;
};
node* create(int preL, int preR, int inL, int inR){
    if(preL > preR) return NULL;
    node* root = new node;
    root->data = pre[preL];
    int k;
    for(k = inL; k <= inR; k++){
        if(in[k] == pre[preL]){
            break;
        }
    }
    int numleft = k-inL;
    root->lchild = create(preL+1, preL+numleft, inL, k-1);
    root->rchild = create(preL+numleft+1, preR, k+1, inR);
    return root;
}
int num = 0;
void postorder(node* root){
    if(root == NULL){
        return;
    }
    postorder(root->lchild);
    postorder(root->rchild);
    printf("%d", root->data);
    num++;
    if(num < n) printf(" ");
}
int main(){
    scanf("%d", &n);
    char str[5];
    stack<int> st;
    int x, preindex = 0, inindex = 0;
    for(int i = 0; i < 2 * n; i++){
        scanf("%s", str);
        if(strcmp(str, "Push") == 0){
            scanf("%d", &x);
            pre[preindex++] = x;
            st.push(x);
        } else {
            in[inindex++] = st.top();
            st.pop();
        }
    }
   node* root = create(0, n - 1, 0, n - 1);
   postorder(root);
   return 0;
}

第一次，1h
int k;
for(int k = inL; k <= inR; k++) { //报错
if(in[k] == pre[preL]){
break;
}
}
k重新定义发现错误