【LeetCode】55. Jump Game (Medium)

【题目】

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.

【解】所有不大于maximum  jump length的距离都可以跳，所以只要看能够跳到的最大距离是不是比最后一个远。

class Solution {public:    bool canJump(vector<int>& nums) {        int n = nums.size();        if (n == 0) return false;        int m = nums[0];        for (int i = 1; i < n; i++) {            if (m < i) return false;//跳不到位置i,可以确定不能跳到最后            if (i + nums[i] > m)//从位置i可以比从之前的位置跳得更远                m = i + nums[i];        }        return true;    }};

时间复杂度O(n)，空间复杂度O(1)