UVA 122 树的层次遍历

这里使用数组来实现二叉树，用整数表示节点编号，left[u]和right[u]分别表示u节点的左孩子和右孩子的节点编号。
这里关键是按照输入建立出二叉树。
对应代码如下：

#include<cstdio>#include<iostream>#include<algorithm>#include<cstring>#include<string>#include<vector>#include<queue>using namespace std;const int maxn = 300;int Left[maxn], Right[maxn],Value[maxn];bool hasValue[maxn];int root;int cnt;bool failed;void newTree(){    cnt = 0;    root = ++cnt;    Left[root] = Right[root] = 0;    hasValue[root] = false;}int newNode(){    ++cnt;    Left[cnt] = Right[cnt] = 0;    hasValue[cnt] = 0;    return cnt;}void addnode(int v, char *s){    int t = root;    for (int i = 0; i < strlen(s)-1; i++){        if (s[i] == 'L'){            if (Left[t] == 0)                Left[t] = newNode();            t = Left[t];        }        else{            if (Right[t] == 0)                Right[t] = newNode();            t = Right[t];        }    }    if (hasValue[t])        failed = true;    hasValue[t] = true;    Value[t] = v;}bool getinput(){    char s[maxn];    failed = false;    newTree();    for (;;){        if (scanf("%s", s) != 1)            return false;        if (!strcmp(s, "()"))            break;        int v;        sscanf(&s[1], "%d", &v);        addnode(v, strchr(s, ',') + 1);    }    return true;}void bfs(vector<int> &ans){    queue<int> q;    ans.clear();    q.push(root);    while (!q.empty()){        int p = q.front();        q.pop();        if (!hasValue[p]){            failed = true;            return;        }        ans.push_back(Value[p]);        if (Left[p] != 0)            q.push(Left[p]);        if (Right[p] != 0)            q.push(Right[p]);    }    return;}int main(){    while (getinput()){        vector<int> ans;        bfs(ans);        if (failed)            cout << "not complete" << endl;        else{            cout << ans[0];            for (int i = 1; i < ans.size(); i++)                cout << " " << ans[i];            cout << endl;        }        memset(hasValue, 0, sizeof(hasValue));    }    return 0;}