leetcode113.路径总和II

Question

给你二叉树的根节点 root 和一个整数目标和 targetSum ，找出所有从根节点到叶子节点路径总和等于给定目标和的路径。
叶子节点是指没有子节点的节点。
示例 1：
输入：root = [5,4,8,11,null,13,4,7,2,null,null,5,1], targetSum = 22 输出：[[5,4,11,2],[5,8,4,5]]
示例 2：
输入：root = [1,2,3], targetSum = 5 输出：[]
示例 3：
输入：root = [1,2], targetSum = 0 输出：[]
提示：
树中节点总数在范围 [0, 5000] 内 -1000 <= Node.val <= 1000 -1000 <= targetSum <= 1000
Related Topics 树深度优先搜索回溯二叉树 👍 745 👎 0

Answer

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//113，跟112相比需要找出所有的路径,dfs
void dfs(TreeNode* root, vector<vector<int>> &res, vector<int> &cur, int targetSum) {
    if (!root)
        return;
    cur.push_back(root->val);
    if (root && !root->left && !root->right && root->val == targetSum) {
        res.push_back(cur);
    }

    dfs(root->left, res, cur, targetSum-root->val);
    dfs(root->right, res, cur, targetSum-root->val);
    cur.pop_back();
}
vector<vector<int>> pathSum(TreeNode* root, int targetSum) {
    vector<vector<int>> res;
    vector<int> cur;
    dfs(root, res, cur, targetSum);
    return res;
}

Question

Answer

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