55. Jump Game leetcode

55. Jump Game

• Total Accepted: 95819
• Total Submissions: 330538
• Difficulty: Medium

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.

贪心算法:正向

 class Solution {
 public:
     bool canJump(const vector<int>& nums) {
         ; //reach the rightest position
         ; i < reach && reach < nums.size(); ++i)
             reach = max(reach, i +  + nums[i]);
         return reach >= nums.size();
     }
 };

//贪心算法,逆向,比正向稍费时

 class Solution {
 public:
     bool canJump (const vector<int>& nums) {
         if (nums.empty()) return true;
         //
         ;
         ; i >= ; --i)
             if (i + nums[i] >= left_most)
                 left_most = i;
         ;
     }
 };

 bool canJump(int* nums, int numsSize) {
     ;
     int flag = true;
     ; i < numsSize ; ++i) {
         int j = i;
         for (; j <= idx + nums[idx]; ++j) {
             if(idx + nums[idx] <= j + nums[j]){
                 idx = j;
                 flag = true;
                 break;
             }else {
                 flag = false;
             }
         }

     }
     )
     return true;
     return false;
 }

9月份人人net来某校宣讲,其中一个编程题即为此题.

 #include <iostream>
 #include <string.h>
 #include <mcheck.h>
 using namespace std;
 bool test(int *arr, int size){
     ;
     ) {
         //cout << idx << endl;
         ) return false;
         idx += arr[idx];
          //cout << idx << endl;
     }
     ) return true;
     else
     return false;
 }

 int main(int argc, char* argv[])
 {
     ,,,,,};
     ]);
     bool flag = test(arr, len);
     cout << flag << endl;
     ,,,,,};
 ]);
     cout << test(a, lena) << endl;
     ;
 }