LeetCode "Jump Game II"

Greedy, Greedy, Greedy.. It is all about maximum interval update.

One trick is, we start looping over each element from the one nearest to end to farthest one - because the nearer the index is, more hopeful it could finish earlier. With this optimization, I got it passed with only 24ms.

class Solution {
public:

int jump(int A[], int n) {
if (n <= 1) return 0;
int last = 0, inx = 0;
int cnt = 0;
while (inx < n)
{
int newMaxInx = 0;
int tmp_i = inx + 1;
while (tmp_i--)
{
if (tmp_i < last) break;
newMaxInx = std::max(newMaxInx, A[tmp_i] + tmp_i);
if (newMaxInx >= n - 1) return cnt + 1;
}
last = inx;
inx = newMaxInx;
cnt++;
}
return cnt;
}
};