Leetcode Week6 Jump Game

Question

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.

Example 1:

Input: [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: [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.

Answer

class Solution {
public:
    bool canJump(vector<int>& nums) {
        int maxJump = 0;
        for (int i = 0; i < nums.size(); i++) {
            if (i <= maxJump) {
                maxJump = max(maxJump, i+nums[i]);
            }
        }
        return maxJump >= nums.size()-1;
    }
};

　　答案比较简单，只需要记录从左往右记录能跳的最大Index即可，当然前提是当前是能被跳到的。