UVA122 Trees on the level

题目链接戳这里

构造一个二叉树 然后用bfs层次遍历二叉树
用到sscanf()函数处理字符串
画画图模拟一下很好明白的

用指针写的

/*  UVA 122#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <queue>#include <vector>#include <cmath>#include <stack>#include <string>#include <map>#include <set>#define pi acos(-1.0)#define LL long long#define ULL unsigned long long#define inf 0x3f3f3f3f#define INF 1e18//#define lson l,mid,rt<<1//#define rson mid+1,r,rt<<1|1#define debug(a) printf("---%d---\n", a);#define mem0(a) memset(a, 0, sizeof(a))#define memi(a) memset(a, inf, sizeof(a))#define mem1(a) memset(a, -1, sizeof(a))using namespace std;typedef pair<int, int> P;const double eps = 1e-10;const int maxn = 1e6 + 5;const int mod = 1e8;int failed, node;struct Node{    int val, flag;    Node* lson;    Node* rson;}tree[maxn]; Node* NewNode(){    Node* p = &tree[node++];    p->flag = p->val = 0;    p->lson = p->rson = NULL;    return p;}void addnode(Node* root, int v, char* s){    Node* p = root;    for (int i = 0; i < strlen(s); i++){ // 从根节点往下走         if (s[i] == 'L'){            if (p->lson == NULL) p->lson = NewNode(); // 结点不存在,建立新结点             p = p->lson;   // 往左走         }        else if (s[i] == 'R'){            if (p->rson == NULL) p->rson = NewNode();            p = p->rson;                }    }    if (p->flag) failed = 1; // 若此结点已经被赋值 failed     p->val = v;    p->flag = 1;} void bfs(Node* root, vector<int>* ans){    queue<Node*> q;    q.push(root);    while (!q.empty()){        Node* p = q.front(); q.pop();        if (p->flag == 0){            failed = 1;        }        (*ans).push_back(p->val);        if (p->lson != NULL) q.push(p->lson);        if (p->rson != NULL) q.push(p->rson);    }}int main(void){//  freopen("C:\\Users\\wave\\Desktop\\NULL.exe\\NULL\\in.txt","r", stdin);    char s[35], str[35];    int v, i;    while (~scanf("%s", s))    {        failed = node = 0;        Node* root = NewNode();  // 根节点         if (strcmp(s, "()") != 0){            sscanf(s, "(%d,%s", &v, str); // 一种写法             addnode(root, v, str);        }else continue;        while (~scanf("%s", s)){            if (strcmp(s, "()") == 0) break;            sscanf(&s[1], "%d", &v); // 另一种写法             addnode(root, v, strchr(s, ',')+1);        }        vector<int> ans;        if (!failed) bfs(root, &ans);        if (failed) puts("not complete");        else {            for (i = 0; i < ans.size(); i++)                printf("%d%c", ans[i], i+1==ans.size()?'\n':' ');           }    }       return 0;}

不用指针写的

#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <queue>#include <vector>#include <cmath>#include <stack>#include <string>#include <map>#include <set>#define pi acos(-1.0)#define LL long long#define ULL unsigned long long#define inf 0x3f3f3f3f#define INF 1e18//#define lson l,mid,rt<<1//#define rson mid+1,r,rt<<1|1#define debug(a) printf("---%d---\n", a)#define mem0(a) memset(a, 0, sizeof(a))#define memi(a) memset(a, inf, sizeof(a))#define mem1(a) memset(a, -1, sizeof(a))using namespace std;typedef pair<int, int> P;const double eps = 1e-10;const int maxn = 1e6 + 5;const int mod = 1e8;int failed, node;struct Node{    int val, flag;    int lson, rson;}tree[maxn];int NewNode(){    tree[++node].val = 0;    tree[node].flag = 0;    tree[node].lson = 0;    tree[node].rson = 0;    return node;}void addnode(int rt, int v, char* s){    for (int i = 0; i < strlen(s); i++){        if (s[i] == 'L'){            if (!tree[rt].lson)                tree[rt].lson = NewNode();            rt = tree[rt].lson;        }        else if (s[i] == 'R'){            if (!tree[rt].rson)                tree[rt].rson = NewNode();            rt = tree[rt].rson;        }    }    if (tree[rt].flag) failed = 1;    tree[rt].val = v;    tree[rt].flag = 1;}vector<int> bfs(int rt){    queue<int> q;    q.push(rt);    vector<int> ans;    while (!q.empty()){        int u = q.front(); q.pop();        if (tree[u].flag == 0){            failed = 1;            break;        }        ans.push_back(tree[u].val);        if (tree[u].lson) q.push(tree[u].lson);        if (tree[u].rson) q.push(tree[u].rson);    }    return ans;}int main(void){//  freopen("C:\\Users\\wave\\Desktop\\NULL.exe\\NULL\\in.txt","r", stdin);    char s[35], str[35];    int v, i;    while (~scanf("%s", s))    {        failed = node = 0;        int root = NewNode();    // 根节点         if (strcmp(s, "()") != 0){            sscanf(s, "(%d,%s", &v, str); // 一种写法             addnode(root, v, str);        }else continue;        while (~scanf("%s", s)){            if (strcmp(s, "()") == 0) break;            sscanf(&s[1], "%d", &v); // 另一种写法             addnode(root, v, strchr(s, ',')+1);        }        vector<int> ans;        if (!failed) ans = bfs(root);        if (failed) puts("not complete");        else {            for (i = 0; i < ans.size(); i++)                printf("%d%c", ans[i], i+1==ans.size()?'\n':' ');           }    }       return 0;}