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

关联问题 55-Jump Game

贪心算法

- currJump 当前的跳数

- currRange 当前跳数所能达到的最大范围

- iRange 在i 位置时所能达到的最大范围

实现

class Solution {
public:
int jump(vector<int>& nums) {
int len = nums.size();
if (len == 0)
return 0;
int currJump=0, currRange=0, iRange = 0;
for (int i = 0; i < len; i++)
{
//如果当前跳数所达到的最大范围不超过i，那么需要跳数增加
if (currRange < i)
{

currJump++;
currRange = iRange;
}
iRange = max(iRange, nums[i] + i);
}
return currJump;
}
};