ALDS1_8_C Tree - Binary Search Tree 3

Calendar Clock iconCalendar Clock icon

AOJ

# 目次

# 解答

// C++ 14
#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <algorithm>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <math.h>

#define ll long long
#define Int int
#define loop(x, start, end) for(Int x = start; x < end; x++)
#define loopdown(x, start, end) for(int x = start; x > end; x--)
#define rep(n) for(int x = 0; x < n; x++)
#define span(a,x,y) a.begin()+x,a.begin()+y
#define span_all(a) a.begin(),a.end()
#define len(x) (x.size())
#define last(x) (*(x.end()-1))

using namespace std;
 
struct Node {
    int key;
    Node *parent, *left, *right;
};
 
Node *root, *NIL;
 
void insert(int key) {
    Node *y = NIL;
    Node *x = root;
    Node *z = (Node *)malloc(sizeof(Node));
 
    z->key = key;
    z->left = NIL;
    z->right = NIL;
 
    while (x != NIL) {
        y = x;
        if (key < x->key) {
            x = x->left;
        } else {
            x = x->right;
        }
    };
    
    z->parent = y;
 
    if (y == NIL) {
        root = z;
        return;
    }
 
    if (key <= y->key) {
        y->left = z;
    } else {
        y->right = z;
    }
};


Node *findNode(Node *node, int key) {
    Node* cur = node;
    while (cur != NIL && cur->key != key) {
        if (key < cur->key) {
            cur = cur->left;
        } else {
            cur = cur->right;
        }
    }
    
    return cur;
}

bool find(Node *node, int key) {
    return findNode(node, key) != NIL;
}

Node *tMin(Node *node) {
    while (node->left != NIL) {
        node = node->left;
    }
    
    return node;
}

Node *tSuccessor(Node *node) {
    if (node->right != NIL) {
        return tMin(node->right);
    }
    
    Node *y = node->parent;
    while (y != NIL && node == y->right) {
        node = y;
        y = y->parent;
    }
    
    return y;
}
 
void tDelete(Node *z) {
    Node *y, *x;
    
    if (z->left == NIL || z->right == NIL) y = z;
    else y = tSuccessor(z);
    
    if (y->left != NIL) {
        x = y->left;
    } else {
        x = y->right;
    }
    
    if (x != NIL) {
        x->parent = y->parent;
    }
    
    if (y->parent == NIL) {
        root = x;

    } else {
        if (y == y->parent->left) {
            y->parent->left = x;
        } else {
            y->parent->right = x;
        }
    }
    
    if (y != z) {
        z->key = y->key;
    }

    free(y);
}

void preorder(Node *node) {
    if (node == NIL) return;
    cout << " " << node->key;
    preorder(node->left);
    preorder(node->right);
}

void inorder(Node *node) {
    if (node == NIL) return;
    inorder(node->left);
    cout << " " << node->key;
    inorder(node->right);
}

int main() {
    int n, x;
    string op;
    cin >> n;
    for (int i=0; i<n; i++) {
        cin >> op;
        if (op[0] == 'i') {
            cin >> x;
            insert(x);
            continue;
        }
        else if (op[0] == 'd') {
            cin >> x;
            tDelete(findNode(root, x));
            continue;
        }

        else if (op[0] == 'f') {
            cin >> x;
            if (find(root, x)) {
                cout << "yes" << endl;
            } else {
                cout << "no" << endl;
            }
            continue;
        }
        else if (op[0] == 'p') {
            inorder(root); cout << endl;
            preorder(root); cout << endl;
            continue;
        }
    }

    return 0;
}

リモートフリーランス。ウェブサービス、スマホアプリエンジニア。
東アジアを拠点に世界を移動しながら活動してます!

お仕事のご依頼・お問い合わせはこちら

コメント