[LeetCode]55.Jump Game

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.

Determine if you are able to reach the last index.

For example:
A = [2,3,1,1,4], return true.

A = [3,2,1,0,4], return false.

思路

用distance记录当前i之前跳的最远距离。如果distance< i，即代表即使再怎么跳跃也不能到达i。当到达i时，A[i]+i，代表从i能跳最远的距离。max(distance,A[i]+i)代表能到达的最远距离。

代码

    /*--------------------------------------------
    *   日期：2014-02-28
    *   作者：SJF0115
    *   题目: 55.Jump Game
    *   网址：https://oj.leetcode.com/problems/jump-game/
    *   结果：AC
    *   来源：LeetCode
    *   博客：
    ------------------------------------------------*/
    #include <iostream>
    #include <vector>
    using namespace std;

    class Solution {
    public:
        bool canJump(int A[], int n) {
            // 记录历史跳最远距离
            int distance = 0;
            for(int i = 0;i < n && i <= distance;++i){
                // A[i]+i当前跳最远距离 distance为i之前跳最远距离
                distance = max(A[i]+i,distance);
            }//for
            if(distance < n-1){
                return false;
            }//if
            return true;
        }
    };

    int main(){
        Solution solution;
        //int A[] = {3,2,1,0,4};
        //int A[] = {2,3,1,1,4};
        int A[] = {2,3,0,1,4};
        cout<<solution.canJump(A,5)<<endl;
        return 0;
    }

运行时间

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