leetcode 55. 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.

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.

Constraints:

1 <= nums.length <= 3 * 10^4
0 <= nums[i][j] <= 10^5

这道题和 45. Jump Game 2 很像。思路就是判断是否会停留在一个值为 0 的位置不动。

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