[leetcode] Jump Game

Given an array of non-negative integers, you are initially positioned at the first index of the array.

Each element in the array represents your maximum jump length at that position.

Determine if you are able to reach the last index.

For example:
A = [2,3,1,1,4], return true.

A = [3,2,1,0,4], return false.

package com.wyt.leetcodeOJ;

/**
 * @author wangyitao
 * @Date 2015-01-05
 * @version 1.0
 * @Description
 * Given an array of non-negative integers, you are initially positioned at the first index of the array.
 * Each element in the array represents your maximum jump length at that position.
 * Determine if you are able to reach the last index.
 * For example:
 * A = [2,3,1,1,4], return true.
 * A = [3,2,1,0,4], return false.
 */
public class JumpGame {

	public static void main(String[] args) {
		int[] A = {1,2,3};
		System.out.println(canJump(A));
	}

	/**
	 * @param A
	 * @return
	 * 
	 * 浠庣涓?釜鍏冪礌寮?锛屼互0~A[0]涓哄尯闂达紝鎵惧埌涓?釜鏈?ぇ鐨勬墿灞曞尯闂达紙0锛孉[x]锛?鍐嶅湪(x, A[x])鍖洪棿涓壘涓嬩竴涓墿灞曞尯闂达紝濡傛灉A.length鍦ㄥ叾涓紝鍒欑粨鏉?
	 */
	public static boolean canJump(int[] A) {
		if(A == null || A.length == 0) {
			return false;
		}
		
		if(A.length == 1) {
			return A[0] >= 0;
		}
		
		int curMax = A[0];
		int result = 0;
        for (int i = 0; i < A.length;) {
        	int step = 0;
        	if (A[i] == 0 || i == A.length-1) {
        		break;
        	}
			for (int j = i + 1; j <= i + (A[i] < A.length-1 ? A[i] : A.length - 1); j++) {
				if (j + A[j] >= A.length) {
					return true;
				}
				if (curMax < j + A[j]) {
					curMax = j + A[j];
					step = j - i;
				}
			}
			i = step == 0 ? i+A[i] : i + step;
			result = i;
		}
        if (result + 1 >= A.length) {
			return true;
		} else {
			return false;
		}
    }
}