【LeetCode】45. Jump Game II

Jump Game II

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.)

 

ret:目前為止的jump數

curRch:從A[0]進行ret次jump之后達到的最大范圍

curMax:從0~i這i+1個A元素中能達到的最大范圍

當curRch < i，說明ret次jump已經不足以覆蓋當前第i個元素，因此需要增加一次jump，使之達到

記錄的curMax。

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