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https://leetcode.com/problems/pascals-triangle-ii/


Recursion –> top down DP memoization

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class Solution {
    // int[][] memo;
    private int getNum(int row,int col){
        if(row==0||col==0||col==row) return 1; 
        // if(memo[row][col]>0) return memo[row][col];
        return memo[row][col]=getNum(row-1,col-1)+getNum(row-1,col);
    }
    public List<Integer> getRow(int rowIndex) {
        List<Integer> ans=new ArrayList<>();
        // memo = new int[rowIndex+1][rowIndex+1];
        for(int i=0;i<=rowIndex;i++){
            ans.add(getNum(rowIndex,i));
        }
        return ans;
    }
}

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