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.
题解：
倒着扫描，看每个点是否可达， 更新最大可达的下标。
class Solution {
public:
bool canJump(vector<int>& nums) {
int n = nums.size();
if (n == 0) {
return false;
}
int k = nums[0];
int reach = n - 1;
for (int i = n - 2; i >= 0; i--) {
if (i + nums[i] >= reach) {
reach = i;
}
}
return reach == 0;
}
};
