Leetcode dynamic planning day 16

64. Minimum path sum

221. The largest square

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64. Minimum path sum

Realize the idea ：

Is very normal , It's no different from yesterday's topic .

Implementation code ：

class Solution {
    public int minPathSum(int[][] grid) {
        int m=grid.length,n=grid[0].length;
        for(int i=0;i<m;i++){
            for(int j=0;j<n;j++){
                if(i==0&&j!=0){
                    grid[0][j]=grid[0][j-1]+grid[0][j];
                }else if(j==0&&i!=0){
                    grid[i][0]=grid[i-1][0]+grid[i][0];
                }else if(i!=0&&j!=0){
                    grid[i][j]=Math.min(grid[i-1][j],grid[i][j-1])+grid[i][j];
                }
            }
        }
        return grid[m-1][n-1];
    }
}

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221. The largest square

Realize the idea ：

For this question , The explanation of the official explanation is very clear ：

  After defining the state transition equation , The code of this problem is easy to write .

Implementation code ：

class Solution {
    public int maximalSquare(char[][] matrix) {
        int m=matrix.length,n=matrix[0].length;
        int[][] dp=new int[m][n];
        int maxSum=0;
        for(int i=0;i<m;i++){
            for(int j=0;j<n;j++){
                if(matrix[i][j]=='0'){
                    dp[i][j]=0;
                }else if(i==0||j==0){
                    dp[i][j]=1;
                }else{
                    dp[i][j]=Math.min(Math.min(dp[i-1][j-1],dp[i-1][j]),dp[i][j-1])+1;
                }
                maxSum=Math.max(dp[i][j],maxSum);
            }
        }
        return maxSum*maxSum;
    }
}