先初步判断是否满足二叉搜索树和小顶堆(针对每一颗最小的子树),如果都满足,进一步判断整棵树是否满足。
1 #include <iostream> 2 #include <string> 3 #include <cstring> 4 using namespace std; 5 typedef struct node 6 { 7 int K1; 8 int K2; 9 int L; 10 int R; 11 }node_arr[1001]; 12 node_arr s; 13 int n; 14 int f[1001];//存放前驱结点,判断是否为小顶堆的时候用到 15 int f_is_BST1 = 0; 16 int f_greater1 = 0; 17 int f_greater2 = 0; 18 void is_BST1(int i)//二叉搜索树的初步判断 19 { 20 if (s[i].L != -1) 21 { 22 if (s[i].K1 > s[s[i].L].K1) 23 { 24 is_BST1(s[i].L); 25 } 26 else 27 { 28 f_is_BST1 = 1; 29 return; 30 } 31 } 32 if (s[i].R != -1) 33 { 34 if (s[i].K1 <= s[s[i].R].K1) 35 { 36 is_BST1(s[i].R); 37 } 38 else 39 { 40 f_is_BST1 = 1; 41 return; 42 } 43 } 44 } 45 void is_greater1(int i)//小顶堆的初步判断 46 { 47 if (s[i].L != -1) 48 { 49 if (s[i].K2 <= s[s[i].L].K2) 50 { 51 is_greater1(s[i].L); 52 } 53 else 54 { 55 f_greater1 = 1; 56 return; 57 } 58 } 59 if (s[i].R != -1) 60 { 61 if (s[i].K2 <= s[s[i].R].K2) 62 { 63 is_greater1(s[i].R); 64 } 65 else 66 { 67 f_greater1 = 1; 68 return; 69 } 70 } 71 } 72 void is_greater2()//小顶堆进一步判断(整棵树) 73 { 74 for (int i = 0; i < n; i++) 75 { 76 int j = i; 77 while (f[j] != -1) 78 { 79 if (s[f[j]].K2 > s[j].K2) 80 f_greater2 = 1; 81 j = f[j]; 82 } 83 } 84 } 85 bool is_BST2(int x, int min, int max)//搜索树进一步判断(整棵树) 86 { 87 if (x == -1)return true; 88 if (s[x].K1 > max || s[x].K1 < min) return false; 89 return (is_BST2(s[x].L, min, s[x].K1 - 1) && is_BST2(s[x].R, s[x].K1, max)); 90 } 91 int main() 92 { 93 int r[1001] = { 0 }; 94 cin >> n; 95 for (int i = 0; i < n; i++)f[i] = -1; 96 for (int i = 0; i < n; i++) 97 { 98 struct node temp; 99 cin >> temp.K1 >> temp.K2 >> temp.L >> temp.R; 100 if (temp.L != -1) 101 { 102 f[temp.L] = i; 103 r[temp.L] = 1; 104 } 105 if (temp.R != -1) 106 { 107 f[temp.R] = i; 108 r[temp.R] = 1; 109 } 110 s[i] = temp; 111 } 112 int root; 113 for (int i = 0; i < n; i++) 114 { 115 if (r[i] == 0)root = i; 116 } 117 for (int i = 0; i < n; i++) 118 is_BST1(i); 119 is_greater1(0); 120 is_greater2(); 121 if (f_is_BST1 == 0 && f_greater1 == 0) 122 if (f_greater2 == 1 || is_BST2(root, -32767, 32767) == false) 123 cout << "NO"; 124 else 125 cout << "YES"; 126 else 127 { 128 cout << "NO"; 129 } 130 return 0; 131 }