[LeetCode65]Pascal's Triangle II

Given an index k, return the kth row of the Pascal's triangle.

For example, given k = 3,
Return [1,3,3,1].

Note:

Could you optimize your algorithm to use only O(k) extra space?

Analysis:

滚动数组实现.

C++

vector<int> getRow(int rowIndex) {      vector<int> result(rowIndex+2,0);    result[1]=1;    for(int i=0;i<rowIndex;i++){        for(int j=rowIndex+1;j>0;j--){            result[j]= result[j-1]+result[j];        }    }    result.erase(result.begin());    return result;    }

java

public List<Integer> getRow(int rowIndex) {        List<Integer> result = new ArrayList<>();        for(int i=0;i<rowIndex+2;i++)        result.add(0);        result.set(1,1);        for(int i=0;i<rowIndex;i++){        for(int j=rowIndex+1;j>0;j--)        result.set(j, result.get(j-1)+result.get(j));        }        result.remove(0);        return result;    }

Java