Two Sum

 

源代码：

import java.util.Arrays;

public class Solution {

    public int[] twoSum(int[] numbers, int target) {

        int[] results = new int[2];

        int len = numbers.length;

        Node[] nodes = new Node[len];

        for (int i = 0; i < len; i++) {

            nodes[i] = new Node(i + 1, numbers[i]);

        }

        /*

        Node tempNode = null;

        

        for (int i = 0; i < len; i++) {

            for (int j = 0; j < len - 1 - i; j++) {

                if (nodes[j].value > nodes[j + 1].value) {

                    tempNode = nodes[j];

                    nodes[j] = nodes[j + 1];

                    nodes[j + 1] = tempNode;

                }

            }

        }

        */

        Arrays.sort(nodes);



        int key = -1, index = -1;

        for (int i = 0; i < len; i++) {

            key = target - nodes[i].value;

            index = binarySearch(nodes, key);

            if (index != -1 && i != index) {

                if (nodes[i].index < nodes[index].index) {

                    results = new int[] { nodes[i].index, nodes[index].index };

                } else {

                    results = new int[] { nodes[index].index, nodes[i].index };

                }

                return results;

            }

        }



        return results;

    }

    

    public int binarySearch(Node[] nodes, int key) {

        int left = 0, right = nodes.length - 1, mid = (left + right) >> 1;



        while (left <= right) {

            mid = (left + right) >> 1;

            if (nodes[mid].value == key) {

                return mid;

            } else if (nodes[mid].value > key) {

                right = mid - 1;

            } else {

                left = mid + 1;

            }

        }

        return -1;

    }



    class Node implements Comparable<Node>{

        int index;

        int value;



        public Node() {

        }



        public Node(int index, int value) {

            this.index = index;

            this.value = value;

        }

        @Override

        public int compareTo(Node node) {



            if (this == node) {

                return 0;

            }

            return this.value - node.value;

        }

    }

}