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package class07 ;
public class Code03_PathSum {
// 测试链接：
public static class TreeNode {
public int val ;
public TreeNode left ;
public TreeNode right ;
TreeNode ( int val ) {
this . val = val ;
}
}
public static boolean isSum = false ;
public static boolean hasPathSum ( TreeNode root , int sum ) {
if ( root = = null ) {
return false ;
}
isSum = false ;
process ( root , 0 , sum ) ;
return isSum ;
}
public static void process ( TreeNode x , int preSum , int sum ) {
if ( x . left = = null & & x . right = = null ) {
if ( x . val + preSum = = sum ) {
isSum = true ;
}
return ;
}
// x是非叶节点
preSum + = x . val ;
if ( x . left ! = null ) {
process ( x . left , preSum , sum ) ;
}
if ( x . right ! = null ) {
process ( x . right , preSum , sum ) ;
}
}
// public static boolean hasPathSum(TreeNode root, int sum) {
// if (root == null) {
// return false;
// }
// return process(root, sum);
// }
//
// public static boolean process(TreeNode root, int rest) {
// if (root.left == null && root.right == null) {
// return root.val == rest;
// }
// boolean ans = root.left != null ? process(root.left, rest - root.val) : false;
// ans |= root.right != null ? process(root.right, rest - root.val) : false;
// return ans;
// }
}
