OJ练习29——T119 Pascal's Triangle II

打印杨辉三角指定行，

返回vector<int>类型。

【思路】

1.照搬前面一道题，保存所有行；

2.最小空间复杂度0(n)，也是题目要求。

即每一行覆盖上一行，为了保证不提前覆盖有效值，需要从后向前算。

【other code】

vector<int> getRow(int rowIndex) {
        vector<int> ret;
        ret.resize(rowIndex+1);
        //ret[0]=1;
        //ret[rowIndex]=1;
        int i,j;
        for(i=0; i<=rowIndex; i++)
        {
            ret[i]=1;
            if(i>1){
                for(j=i-1; j>0; j--)
                    ret[j]=ret[j]+ret[j-1];
            }
        }
        return ret;
    }

【结果】

3ms，其实很简单，不赘述。

OJ练习29——T119 Pascal's Triangle II

时间： 2024-11-13 04:18:00

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