day9

1.剑指 Offer 42. 连续子数组的最大和

 dp数组:dp[i]是指以i结尾的连续子数组的最大和

 res是在dp[0]--dp[i]里找到最大值

 1 class Solution {
 2 public:
 3     int dp[100001];
 4     int maxSubArray(vector<int>& nums) {
 5       int n = nums.size();
 6       int res = dp[0] = nums[0];
 7       for(int i = 1;i < n;i ++){
 8        dp[i] = max(dp[i - 1] + nums[i],nums[i]);
 9        res = max(res,dp[i]);
10      }
11      return res;
12     }
13 };

2.剑指 Offer 47. 礼物的最大价值

 1 class Solution {
 2 public:
 3     int dp[201][201];
 4     int maxValue(vector<vector<int>>& grid) {
 5       int m = grid.size(),n = grid[0].size();
 6       dp[0][0] = grid[0][0];
 7       for(int i = 0;i < m;i ++){
 8           for(int j = 0;j < n;j ++){
 9               if(i - 1 >= 0 && j - 1 >= 0)
10                dp[i][j] = max(dp[i - 1][j] + grid[i][j],dp[i][j - 1] + grid[i][j]);
11               else if(i - 1 >= 0)
12                dp[i][j] = dp[i - 1][j] + grid[i][j];
13               else if(j - 1 >= 0)
14                dp[i][j] = dp[i][j - 1] + grid[i][j];
15           }
16       }
17       return dp[m - 1][n - 1];
18     }
19 };

 

posted @ 2022-07-06 22:37  balabalahhh  阅读(23)  评论(0)    收藏  举报