55. Jump Game

You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length at that position.

Return true if you can reach the last index, or false otherwise.

 

Example 1:

Input: nums = [2,3,1,1,4]
Output: true
Explanation: Jump 1 step from index 0 to 1, then 3 steps to the last index.

Example 2:

Input: nums = [3,2,1,0,4]
Output: false
Explanation: You will always arrive at index 3 no matter what. Its maximum jump length is 0, which makes it impossible to reach the last index.

 

public boolean canJump(int[] nums) {
    int maxLocation = 0;
    for (int i = 0; i < nums.length; i++) {
        if (maxLocation < i)
            return false; //如果上一个maxLocation 小于i，说明到不了这个地方。例如当前位置index是4，但是之前最多能到3，所以到不了4处，更到不了结尾处
        maxLocation =  Math.max(i + nums[i], maxLocation); //看这个位置最多能到什么地方(即i + nums[i])，如果大于当前maxLocation ，就更新maxLocation
    }
    return true;
}