LeetCode112 Path Sum

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详细见：leetcode.com/problems/path-sum

Java Solution: github

package leetcode;import java.util.LinkedList;import java.util.Queue;import tools.TreeNode辅助.TreeNode;/* * Given a binary tree and a sum, determine if the tree has a root-to-leaf *  path such that adding up all the values along the path equals the given sum.For example:Given the below binary tree and sum = 22,              5             / \            4   8           /   / \          11  13  4         /  \      \        7    2      1return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22. */public class P112_PathSum {public static void main(String[] args) {}/* * AC * 4 ms */static class Solution {    public boolean hasPathSum(TreeNode root, int sum) {    if (root == null) {    return false;    }    boolean isDone = false;    Queue<TreeNode> q1 = new LinkedList<>();    Queue<Integer> q2 = new LinkedList<>();    q1.add(root);    q2.add(root.val);    int depth_now = 1;    while (! q1.isEmpty()) {    TreeNode root_now = q1.poll();    depth_now = q2.poll();    if (root_now.left == null && root_now.right == null && depth_now == sum) {    isDone = true;    break;    }    if (root_now.left != null) {    q1.add(root_now.left);    q2.add(depth_now + root_now.left.val);    }    if (root_now.right != null) {    q1.add(root_now.right);    q2.add(depth_now + root_now.right.val);    }    }        return isDone;    }}}

C Solution: github

/*    url: leetcode.com/problems/path-sum    AC 6ms 27.83%*/#include <stdio.h>#include <stdlib.h>struct TreeNode {    int val;    struct TreeNode *left;    struct TreeNode *right;};typedef int bool;typedef struct TreeNode stn;typedef struct TreeNode * ptn;ptn tn_init(int val) {    ptn n = (ptn) malloc(sizeof(stn));    n->val = val;    n->left = NULL;    n->right = NULL;    return n;}typedef ptn T;typedef struct al sal;typedef struct al * pal;struct al {    int capacity;    int size;    T* arr;};pal al_init(int capacity) {    pal l = (pal) malloc(sizeof(sal));    if (capacity < 1) return NULL;    l->arr = (T*) malloc(sizeof(T) * capacity);    l->capacity = capacity;    l->size = 0;    return l;}void al_expand_capacity(pal l) {    T* new_arr = (T*) malloc(sizeof(T) * (l->capacity * 2 + 1));    int i = 0;    for (i = 0; i < l->capacity; i ++)        new_arr[i] = l->arr[i];    free(l->arr);    l->arr = new_arr;    l->capacity = l->capacity * 2 + 1;}void al_add_last(pal l, T v) {    if (l->capacity == l->size) al_expand_capacity(l);    l->arr[l->size] = v;    l->size ++;}void al_free_all(pal l) {    free(l->arr);    free(l);}void swap_al(pal* l1, pal* l2) {    pal t = *l1;    *l1 = *l2;    *l2 = t;}void search(ptn n, int c, int s, int* sign) {    if (*sign) return;    if (n == NULL) return;    search(n->left, c+n->val, s, sign);    search(n->right, c+n->val, s, sign);    if (n->left == NULL && n->right == NULL && c+n->val == s) *sign=1;}bool hasPathSum(ptn n, int s) {    int c = 0, sign = 0;    search(n, 0, s, &sign);    return sign;}

Python Solution: github

#coding=utf-8'''    url: leetcode.com/problems/path-sum    @author:     zxwtry    @email:      zxwtry@qq.com    @date:       2017年4月30日    @details:    Solution: 79ms 46.08%'''class TreeNode(object):    def __init__(self, x):        self.val = x        self.left = None        self.right = Noneclass Solution(object):    def search(self, n, s, a):        if n == None: return False        if n.left == None and n.right == None:            if s == a+n.val: return True        return self.search(n.left, s, a+n.val) \            or self.search(n.right, s, a+n.val)            def hasPathSum(self, n, s):        """        :type n: TreeNode        :type s: int        :rtype: bool        """        return self.search(n, s, 0)

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