**Objective: **Given a binary tree, find the sum of all the nodes which are left as well as leaves nodes.

**Example:**

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** **

**Approach**:

- Approach is quite simple.
- Do the inorder traversal
- check if node if the left child and leaf node.
- If yes then add it to the sum.
- See the code for more understanding.

**Complete Code:**

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public class LeftLeavesSum { | |

// Do the inorder traversal | |

// check if node if the left child and leaf node | |

// if yes then add it to the sum | |

public static int leftLeavesSum = 0; | |

public static void leftSum(Node root, Node parent) { | |

if (root != null) { | |

leftSum(root.left, root); | |

if (root.left == null && root.right == null && parent.left == root) { | |

leftLeavesSum += root.data; | |

} | |

leftSum(root.right, root); | |

} | |

} | |

public static void main(String args[]) { | |

Node root = new Node(10); | |

root.left = new Node(5); | |

root.right = new Node(15); | |

root.left.left = new Node(10); | |

root.left.right = new Node(12); | |

root.left.right.left = new Node(6); | |

root.right.right = new Node(8); | |

root.right.right.left = new Node(5); | |

leftSum(root, root); | |

System.out.println("Sum of left leaves: " + leftLeavesSum); | |

} | |

} | |

class Node { | |

int data; | |

Node left; | |

Node right; | |

public Node(int data) { | |

this.data = data; | |

this.left = null; | |

this.right = null; | |

} | |

} |

**Output:**

Sum of left leaves: 21