PAT 1110

PAT 1102的变形,注意1110需要支持2位数操作,层序遍历的时候检查中间是否有缺漏结点就可以了

#include <iostream>#include <string>#include <cstring>#include<algorithm>#include<cmath>#include <vector>#include <map>#include<stack>#include<queue>#include <stdio.h>using namespace std;#define MAX 20000+5#define INF 0x3f3f3f3fstruct BTree {int lchild, rchild;}t[MAX];int n;int main(){int  i, root = -1;int node[250];char c1[10], c2[10];scanf("%d", &n);memset(node, 0, sizeof(node));for (i = 0; i < n; i++) {cin >> c1 >> c2;if (c1[0] == '-') {t[i].lchild = -1;}else {sscanf(c1, "%d", &t[i].lchild);node[t[i].lchild] = 1;}if (c2[0] == '-') {t[i].rchild = -1;}else {sscanf(c2, "%d", &t[i].rchild);node[t[i].rchild] = 1;}}for (i = 0; i < n; i++) {if (node[i] == 0) {root = i;break;}}queue<int>q;int cnt = 1, flag = 0, tmp;q.push(root);while (!q.empty()) {tmp = q.front();q.pop();if (t[tmp].lchild == -1) {flag = 1;break;}q.push(t[tmp].lchild);cnt++;if (cnt == n)break;if (t[tmp].rchild == -1) {flag = 1;break;}q.push(t[tmp].rchild);cnt++;if (cnt == n)break;}if (n == 1) {printf("YES 0\n");return 0;}if (flag)printf("NO %d\n", root);elseprintf("YES %d\n", t[tmp].rchild == -1 ? t[tmp].lchild : t[tmp].rchild);return 0;}