dp2

62. 不同路径

class Solution {
public:
    int uniquePaths(int m, int n) {
        int answer = 0;
        vector<vector<int>> dp(m, vector<int>(n, 0));
        for(int i = 0; i < m; i++)
        {
            dp[i][0] = 1;
        }
        for(int i = 0; i < n; i++)
        {
            dp[0][i] = 1;
        }
        for(int i = 1; i < m; i++)
            for(int j = 1; j < n; j++)
            {
                dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
            }
        return dp[m - 1][n - 1];
    }
};

63. 不同路径 II

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
  
        vector<vector<int>> dp(obstacleGrid.size(), vector<int>(obstacleGrid[0].size(), 0));

        for(int i = 0; i < obstacleGrid.size(); i++)
        {
            if(obstacleGrid[i][0] == 0)
                dp[i][0] = 1;
            else
                break;
        }
        for(int i = 0; i < obstacleGrid[0].size(); i++)
        {
            if(obstacleGrid[0][i] == 0)
                dp[0][i] = 1;
            else
                break;
        }
        for(int i = 1; i < obstacleGrid.size(); i++)
            for(int j = 1; j < obstacleGrid[0].size(); j++)
            {
                if(obstacleGrid[i][j] == 0)
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
            }
        return dp[obstacleGrid.size() - 1][obstacleGrid[0].size() - 1];
    }
};

343. 整数拆分

class Solution {
public:
    int integerBreak(int n) {
        vector<int> dp(n + 2, 0);
        dp[1] = 1;
        for(int i = 2; i <= n; i++)
        {
            for(int j = 1; j <= i - 1; j++)
            {
                dp[i] = max(dp[i], dp[i - j] * j);
                dp[i]=max(dp[i], j * (i - j));
            }
                
        }
        return dp[n];
    }
};