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:
这个题目居然是动态规划的思想,逐个计算数组中每个元素能够到达的最远的位置(在程序中用reach表示),如用动态数组nums,数组中的元素,nums[i]能到达的最远位置reachi = nums[i]+i,使用reach的更新方式为:reach = max{nums[i]+i,reach}。当对元素遍历的索引大于reach时,说明永远也不能到达最后一个元素,马上返回false,当reach >= nums.size() - 1时返回true。
代码:
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
vector<int> nums;
bool canJump(vector<int> nums){
int reach = 0;
int i;
for(i = 0; i < nums.size(); i++){
if(i > reach){
return false;
}
reach = max(nums[i]+i,reach);
if(reach >= nums.size() - 1){
return true;
}
}
}
int main(){
int n,i,number;
cin>>n;
for(i = 0; i < n; i++){
cin>>number;
nums.push_back(number);
}
if(canJump(nums)){
cout<<"true"<<endl;
}else{
cout<<"false"<<endl;
}
return 0;
}