init commit

archive/algorithm/struct/tree/binary_tree.c

@@ -0,0 +1,139 @@
+#include <memory.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct tree tree;
+
+struct tree {
+    tree* left;
+    tree* right;
+    int val;
+};
+
+tree* new_tree() {
+    tree* t = malloc(sizeof(tree));
+    memset(t, 0, sizeof(tree));
+    return t;
+}
+
+int add_tree(tree* root) {
+    int val = 0;
+    printf("value:");
+    scanf("%d", &val);
+    root->val = val;
+    int flag = 0;
+    while (1) {
+        printf("left(1) or right(2) or upper(3) or quit(any):");
+        scanf("%d", &flag);
+        if (flag == 1) {
+            if (root->left == NULL) {
+                root->left = new_tree();
+            }
+            if (!add_tree(root->left)) break;
+        } else if (flag == 2) {
+            if (root->right == NULL) {
+                root->right = new_tree();
+            }
+            if (!add_tree(root->right)) break;
+        } else if (flag == 3) {
+            return 1;
+        } else {
+            break;
+        }
+    }
+    return 0;
+}
+
+//前;中;后序遍历 dfs
+void print_tree_before(tree* root) {
+    if (root == NULL) {
+        return;
+    }
+    printf("%d\t", root->val);
+    print_tree_before(root->left);
+    print_tree_before(root->right);
+}
+
+void print_tree_stack(tree* root) {
+    //使用栈来实现前序(不是递归)
+    tree* stack[100] = {NULL};
+    int start = 0, end = 0;
+    stack[0] = root;
+    while (end >= 0) {
+        //弹出栈顶
+        int top = end--;
+        tree * tmp=stack[top];
+        printf("%d\t", tmp->val);
+        //右入
+        if (tmp->right != NULL) {
+            stack[++end] = tmp->right;
+        }
+        //左入
+        if (tmp->left != NULL) {
+            stack[++end] = tmp->left;
+        }
+    }
+}
+
+void print_tree_mid(tree* root) {
+    if (root == NULL) {
+        return;
+    }
+    print_tree_mid(root->left);
+    printf("%d\t", root->val);
+    print_tree_mid(root->right);
+}
+
+void print_tree_after(tree* root) {
+    if (root == NULL) {
+        return;
+    }
+    print_tree_after(root->left);
+    print_tree_after(root->right);
+    printf("%d\t", root->val);
+}
+
+//层次遍历 bfs
+void print_tree_cengci(tree* root) {
+    tree* queue[100] = {NULL};
+    int pos = 0;  //队首
+    int end = 0;  //队尾
+    queue[0] = root;
+    while (queue[pos] != NULL) {
+        if (queue[pos]->left != NULL) {
+            //入队
+            queue[++end] = queue[pos]->left;
+        }
+        if (queue[pos] != NULL) {
+            queue[++end] = queue[pos]->right;
+        }
+        //输出(出队)
+        printf("%d\t", queue[pos++]->val);
+    }
+}
+
+int main() {
+    tree* root = new_tree();
+    root->left = new_tree();
+    root->right = new_tree();
+    root->left->left = new_tree();
+    root->left->right = new_tree();
+    root->left->left->val = 4;
+    root->left->right->val = 5;
+    root->val = 1;
+    root->left->val = 2;
+    root->right->val = 3;
+    // add_tree(root);
+    print_tree_before(root);
+    printf("\n");
+    print_tree_mid(root);
+    printf("\n");
+    print_tree_after(root);
+    printf("\n");
+    print_tree_cengci(root);
+    printf("\n");
+    print_tree_stack(root);
+    printf("\n");
+    system("pause");
+    return 0;
+}