1 #include<cstdio> 2 #include<cstdlib> 3 #include<cstring> 4 #include<vector> 5 using namespace std; 6 char a[105]; 7 struct Node{ 8 Node *lson; 9 Node *rson; 10 char data[105]; 11 bool brackets = 0; 12 }; 13 char b[105]; 14 int num; 15 bool sign = 1; 16 vector<char>sy[6]; 17 Node *Structure(){ 18 Node *head, *p_node, *q_node, *d_node; 19 while(a[num] != ' '){ 20 if(a[num] == ')'){ 21 num++; 22 return head; 23 } 24 if(a[num] == '('){ 25 int tmp = num++; 26 sign = 1; 27 if(tmp){ 28 d_node -> rson = Structure(); 29 d_node -> rson -> brackets = 1; 30 } 31 else { 32 p_node = Structure(); 33 sign = 1; 34 } 35 } 36 int cnt = 0; 37 while(a[num] >= '0' && a[num] <= '9' || a[num] == '.'){ 38 b[cnt++] = a[num++]; 39 } 40 if(cnt){ 41 b[cnt] = ' '; 42 p_node = (Node*)malloc(sizeof(Node)); 43 strcpy(p_node -> data, b); p_node -> lson = NULL; p_node -> rson = NULL; 44 if(!sign){ 45 d_node -> rson = p_node; 46 } 47 } 48 else { 49 b[cnt++] = a[num++];b[cnt] = ' '; 50 if(sign){ 51 d_node = head = (Node*)malloc(sizeof(Node)); 52 strcpy(head -> data, b); head -> lson = p_node; 53 sign = 0; 54 } 55 else { 56 q_node = head; 57 d_node = (Node*)malloc(sizeof(Node)); 58 strcpy(d_node -> data, b); 59 while(1){ 60 bool flag = 0; 61 for(int i = 0; i < sy[q_node -> data[0]].size(); i++){ 62 if(sy[q_node -> data[0]][i] == b[0]){ 63 flag = 1; 64 break; 65 } 66 } 67 if(flag){ 68 d_node -> lson = q_node; 69 if(q_node == head){ 70 head = d_node; 71 } 72 else { 73 p_node -> rson = d_node; 74 } 75 break; 76 } 77 else { 78 if(q_node -> rson -> rson && !q_node -> rson -> brackets){ 79 p_node = q_node; 80 q_node = q_node -> rson; 81 } 82 else{ 83 d_node -> lson = q_node -> rson; 84 q_node -> rson = d_node; 85 break; 86 } 87 } 88 } 89 } 90 } 91 } 92 return head; 93 } 94 void Preorder_traversal(Node *p_node){ 95 if(p_node){ 96 printf("%s", p_node -> data); 97 Preorder_traversal(p_node -> lson); 98 Preorder_traversal(p_node -> rson); 99 } 100 } 101 void Inorder_traversal(Node *p_node){ 102 if(p_node){ 103 Inorder_traversal(p_node -> lson); 104 printf("%s", p_node -> data); 105 Inorder_traversal(p_node -> rson); 106 } 107 } 108 void Postorder_traversal(Node *p_node){ 109 if(p_node){ 110 Postorder_traversal(p_node -> lson); 111 Postorder_traversal(p_node -> rson); 112 printf("%s", p_node -> data); 113 } 114 } 115 double Number(char ch[105]){ 116 return atof(ch); 117 } 118 char *Charater_string(double x){ 119 char ch[105]; 120 sprintf(ch, "%f", x); 121 return ch; 122 } 123 char *Count(Node *p_node){ 124 if(p_node -> lson -> lson){ 125 Count(p_node -> lson); 126 } 127 if(p_node -> rson -> rson){ 128 Count(p_node -> rson); 129 } 130 if(p_node -> lson -> lson == NULL && p_node -> rson -> rson == NULL){ 131 double x = Number(p_node -> lson -> data); 132 double y = Number(p_node -> rson -> data); 133 delete(p_node -> lson -> lson); 134 delete(p_node -> lson -> rson); 135 delete(p_node -> rson -> lson); 136 delete(p_node -> lson -> rson); 137 p_node -> lson = NULL; 138 p_node -> rson = NULL; 139 switch(p_node -> data[0]){ 140 case '+': strcpy(p_node -> data, Charater_string(x+y));break; 141 case '-': strcpy(p_node -> data, Charater_string(x-y));break; 142 case '*': strcpy(p_node -> data, Charater_string(x*y));break; 143 case '/': strcpy(p_node -> data, Charater_string(x/y));break; 144 } 145 } 146 return p_node -> data; 147 } 148 int main(){ 149 while(~scanf("%s", a)){ 150 sy['-'].push_back('+'); 151 sy['-'].push_back('-'); 152 sy['*'].push_back('+'); 153 sy['*'].push_back('-'); 154 sy['/'].push_back('+'); 155 sy['/'].push_back('-'); 156 sy['/'].push_back('*'); 157 sy['/'].push_back('/'); 158 num = 0; 159 sign = 1; 160 Node *head = Structure(); 161 puts("Preorder traversal:"); 162 Preorder_traversal(head); 163 puts(""); 164 puts("Inorder traversal:"); 165 Inorder_traversal(head); 166 puts(""); 167 puts("Postorder traversal:"); 168 Postorder_traversal(head); 169 puts(""); 170 puts("Computed result is "); 171 printf("%s ", Count(head)); 172 } 173 return 0; 174 }