LeetCode 45.Jump Game II

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.

Your goal is to reach the last index in the minimum number of jumps.

For example:
Given array A = [2,3,1,1,4]

The minimum number of jumps to reach the last index is 2. (Jump 1 step from index 0 to 1, then 3 steps to the last index.)

分析与解答：

用curRch记录第result步能走到的最大距离，用curMax记录从0到i不管怎么走所能达到的最大距离。当i > curRch之后，就说明i这个位置是现在所不能达到的了，所以要多走一步。那么多走一步能走到哪呢？其实就是curMax。想明白这一点，程序就好写了。

class Solution {
public:
    int jump(int A[], int n) {
        int curMax = 0,curRch = 0,result = 0;
        for(int i = 0;i < n;++i){
            if(i > curRch){
                curRch = curMax;
                ++result;
            }
            curMax = max(curMax,A[i]+i);
        }
        return result;
    }
};