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.

給定一個非負整數陣列，你最初位於陣列的第一個位置。

陣列中的每個元素代表你在該位置可以跳躍的最大長度。

判斷你是否能夠到達最後一個位置。

class Solution {
public:
    int dp[100010];
    bool dfs(vector<int>& nums, int cur, int final){
        if(~dp[cur]) return dp[cur];
        if(cur == final) return true;
        dp[cur] = 0;
        for(int i = 1;i <= nums[cur]; ++i){
            if(dfs(nums, min(cur+i, final), final)) return dp[cur] = 1, true;
        }
        return false;
    }
    bool canJump(vector<int>& nums) {
        memset(dp, -1, sizeof(dp));
        return dfs(nums, 0, nums.size()-1);
    }
};