Knowledge base: 1. matrix : double loop 2 dp similar to one dimension first initialize the value then the dp[i][j]=dp[i-1][j]+dp[i][j-1]; public int uniquePaths(int m, int n) { int[][] dp=new int[m][n]; for(int i=0;i<m;i++){ dp[i][0]=1; } for(int j=0;j<n;j++){ dp[0][j]=1; } for(int i=1;i<m;i++){ for(int j=1;j<n;j++){ dp[i][j]=dp[i][j-1]+dp[i-1][j]; } } return dp[m-1][n-1]; } |